Due to the space limitations of a text message, please note that it is particularly important to read carefully, pay close attention to the context of the question, and use the answers as a springboard for further study.

If you would like my phone number to submit questions, please leave a comment and I will send it to you.

Q: What is the halacha for yom kippur?  I am pregnant, and the doctor said I should definitely eat/drink if I start to feel faint. If I do need to have something, what should I have and how do I measure the amount?

A: Drinking: Fill up your mouth with as much water as it can possibly hold, then expel all of the water into a disposable cup.  Empty half of the water into a second cup.  Slightly less than this quantity is the amount you can drink each time, so make a mark slightly below the level of the water on one of the cups with a marker (R. Yosef Zvi Rimon).  You can drink this amount (of either water or fruit juice, etc.) every 4 or 5 minutes, and if more is needed after only waiting 2 or 3 minutes.

If you need to eat, you can eat the amount of food that equals the approximate volume of a small box of matches (about 1 fl. oz./30 ml) every 9 minutes.  If necessary, it may be eaten every 4.5 minutes.

Eating and drinking don’t combine, so you can do both in the same time period.

If one has a medical need to consume more than the amounts above she should eat and drink normally.

Q: I need to swallow medication every day.  What do I do on Yom Kippur?

A: If possible, it should be swallowed without water.  One may also use a small amount of a liquid that is not normally considered food to swallow the pill, for example water mixed with a bitter substance (like highly concentrated tea essence), mouthwash, lemon juice diluted with a small amount of water, salt water, or water with a drop of liquid soap added to it.  If one must take the medicine in order to prevent the development of a serious medical condition, and certainly if one suffers from a potentially life threatening situation, it may be taken with a bit of water.

Source: Rabbi Isaacs Blog

Due to the space limitations of a text message, please note that it is particularly important to read carefully, pay close attention to the context of the question, and use the answers as a springboard for further study.

If you would like my phone number to submit questions, please leave a comment and I will send it to you.

Q: I am not a bechor, but I fast anyway on Taanis Bechorim (Fast of the Firstborn) on behalf of my firstborn son.  I am not going to be able to attend a siyum this year.  Is it true that I am obligated to fast for my son?

A: I did not find any dissenting opinions regarding the minhag for a father to fast for his firstborn son. However there are several options:
Option 1: Fast
Option 2: Learn Maseches Tamid – the shortest masechta – and make your own siyum
Option 3: “Redeem” the fast, i.e. give tzedaka instead of fasting. This is discussed by the Rama in the end of 334, and R. Avigdor Nebentzal suggests (in his edition of the Mishna Berurah) it in several circumstances regarding the fast of the Bechorim.
Option 4: Mishna Berurah says one may rely on Rabeinu Yechiel’s opinion when necessary. (Mordechai states in the name of Rabbeinu Yechiel that the custom of the firstborns is only to refrain from eating bread and other baked goods, but meat, fish, fruits, vegetables, and the like are permissible.)
I’m not sure if option 3 or 4 is preferable.

Q: Is it OK to serve at the seder meat that was braised and then cooked in liquid (3/4 of the meat will be immersed)?

A: Yes that is allowed.  Even according to the standard approach to the custom of not eating roasted food on the seder nights, cooking in a pot with any amount of liquid is ok since it’s considered cooking by the halacha rather than roasting (this is the implication of MB 476:1 ) even though people commonly refer to this as roasting.  Aruch Hashulchan (476) would certainly allow it.  He argues that since the Korban Pesach would be invalidated if it was cooked in a pot without any liquid it is therefore even permitted to eat meat cooked in a pot in its own juices without any additional liquid whatsoever.

Q:  If I need to daven in an airport, can I use the non-denominational chapel?

A:  According to R. Moshe Feinstein, it is permitted (Masores Moshe.  Some authorities are strict (they consider it a place of idolatry since it is designated for all faiths, some of which are avoda zara (Halachos for the Traveler by R. Donneal Epstein), but they may have looked at it differently had they known R. Feinstein’s opinion which was published posthumously, after the publication of the former book).

Q: Hot meat stew was transferred into a serving dish, then placed on a glass dairy plate. The plate was used for hot food within 24 hours but it was pareve. Do the plate and silverware need to be kashered?

A: Nothing needs to be kashered (since the plate and silverware have a halacha of keli shelishi which is not hot enough to transfer taste.  Even though the stew contains pieces of solid food, it doesn’t have a “davar gush” status due to the liquid that surrounds it (Pischei Teshuva).

Q: If I only have left handed Tefillin to put on, do I put it on my right hand, left hand or not at all?

A: You can use them, but you must wear it backwards/upside down, so the knot is towards your heart (putting the knot near the heart is an actual halacha, whereas the upward orientation of the side channel of the Tefillin that the strap passes through is merely a minhag – Aruch Hashulachan/Biur Halacha siman 27).   You will have to take the strap out of the loop and put it in backwards for this to work (Piskei Teshuvos).

Q: I bought a new pan and I didn’t get to tovel it yet.  Can I cover it with parchment paper or foil and use it until I am able to tovel it?

A: In general this should not be done, since the overwhelming majority of authorities do not allow this.  In their view, the covering just becomes an extension of the pan (see, for example Masores Moshe I pg. 222, Chelkas Binyamin 120:34).  However since there is a minority view that allows it without reservation (R. Avigdor Nebenzahl אסיפת יצחק כ”ד ניסן תשס”ח, also R. Yitzchak Abadi אסיפת יצחק ב’ ניסן תשס”ח) it is OK in very pressing circumstances.

Source: Rabbi Isaacs Blog

From my teachers in yeshiva, I heard many ideas, thoughts and concepts.  One of the ideas that I think about and continue to be inspired by time and again has to do with the general topic of chesed – acts of kindness.  It must first be prefaced that yeshiva is a place that generally promotes, reinforces and emphasizes the primacy of Torah study and intellect, even over other mitzvos and other constructive interests and preoccupations.  In this milieu, those few yeshiva teachers that stressed the importance of helping others – doing chesed – were somewhat counter-cultural vis-à-vis their colleagues, since chesed often must be done at the expense of Torah study.  But the teachers that went so far to claim that the greatest Torah scholars with the most legendary intellects also spent the most time worrying about and helping the less fortunate, were visionaries and their teachings still inspire me.

For the most dedicated traditional-Torah academics, there is no ivory tower.  There is no aloofness from the amecha – the rank and file of the people.  The pairing of Torah excellence and chesed was personified by R. Chaim Soloveitchik (1853 – 1918).  He was the greatest Torah scholar of his generation and the most innovative in several generations, but nevertheless his house was open to all to the extent that it became a public thoroughfare where notices and advertisements were posted.  The extent that he went to to help even those oppositional to traditional observance was legendary.  It should not be surprising then, that he also spoke about the topic of chesed at the expense of Torah study with trademark clarity and wit.  I recently found a story in which he poetically and powerfully expressed his thoughts on the matter.

One time several rabbis were meeting together at R. Chaim Soloveitchik’s home, and one thing they spoke about was Rabbi Eliyahu Chaim Meisel from Lodz.  One of the rabbis said that it’s true that R. Meisel spearheads much tzedaka and does a lot of chesed, but it has resulted in his neglect of his Torah scholarship [and, apparently, this was relevant to the conversation for some reason].  When R. Chaim heard this, he became very upset and declared:

“A rabbi that doesn’t close his Gemara to do tzedaka and chesed – even when the Gemara is open in front of him, it’s as if it’s closed.  However the converse is also true – a rabbi that does close his Gemara to do tzedaka and chesed, even when it’s closed, it’s as if it’s open!¹”

R. Chaim’s ancestor, the great R. Chaim Volozhin, also emphasized chesed in an extreme way.  See the details in a prior post here.

I haven’t begun to live up to this ideal, but it is the goal that I will always shoot for.

Footnotes:

¹ Technical details: This episode is related by R. Meshulam Dovid Soloveitchik, in his Shiurim on the Torah (end of Parashas Eikev), in the name of his father R. Yitzchak Zev Soloveitchik.  He explains that normally interruptions disturb one’s learning since it takes a while to regain concentration.  In this case, however, since the interruption was for the sake of a mitzvah that was necessary to perform, the person will, via divine assistance, not need to invest time to reorient himself in the learning topic because the mitzvah performance is in sync with it.

Source: Rabbi Isaacs Blog

The centerpiece of Parashat Ki Tavo is the section of the Rebuke (Toachacha) which details the suffering that could befall the Jewish nation if they would rebel against the Almighty.  One of the terrible misfortunes that it specifies is “you will plant a vineyard, but you will not render it profane.”  This is a reference to the lesser-known mitzvah of Kerem Revai, literally fourth year vineyard.  It is one of the many agricultural commandments that are reflective of the Jewish people’s connection to its land.  As described in Leviticus 19, a vineyard’s fourth year is the first opportunity that the owner can benefit from its fruits, but they have a unique restriction.  They must be imported to Jerusalem and may only be eaten within its walls.  Alternatively, the fruits can be exchanged for money (referred to by the verse as “profaning”) that must then be spent on food in Jerusalem.  The misfortune of “you will plant a vineyard, but you will not render it profane” means that we will not have the opportunity to travel to Jerusalem to buy food there (after transferring the special status of the fruits onto coins).  It is certainly painful to work the land and tend a fledgling vineyard for three years, all the while looking forward to finally benefiting from them in the fourth year and then suddenly being deprived of that benefit.  But what about after the fourth year?  Isn’t being deprived of the fifth year fruits worse?  It’s true that the fourth year is the first opportunity to benefit from the fruits of the new vineyard, but the benefit is limited by the Jerusalem restrictions detailed above.  Regarding the fifth year fruits, however, the owner is invested in them more, due to an additional year of work, and he would have been able to enjoy them even more than the fourth year fruits, in a complete, unfettered way.  The fifth year fruits can be eaten anywhere in the world.  The loss of fifth year fruits therefore seems more grave than the loss of fourth year fruits.  When admonishing the people with this prophetic warning, why did the Torah choose the less severe fruit/vineyard-loss instead of the more devastating one?

It seems that in truth being deprived of the fourth year fruits is actually worse because of the impact of the canceled trip to Jerusalem.  The purpose of the commandments that require taking fruits to Jerusalem is revealed elsewhere in the Torah – regarding the sister-law of fourth year fruits, Ma’aser Sheni the second tithe, in Deuteronomy 14.  There it says that the purpose of bringing the fruits to Jerusalem was so that the owner would have to spend additional time each year absorbing the holy atmosphere of the city.  A visit to Jerusalem of old was a spiritual experience with no contemporary parallel.  It was a city full of scholars and the daily Temple service.  To lose the fifth year fruits is tough.  All of that work for was for nothing.  The runway was wide open – you could eat them anywhere, sell them, or feed them to your livestock if you had wanted to.  Now they are all gone.  But to lose the opportunity for spiritual enhancement that comes with a pilgrimage to Jerusalem is – or should be – even more devastating.  The message of the warning of the fourth year fruits is that sometimes we pretend our uniquely human capacity for spirituality isn’t there.  We live with the illusion that material satisfaction feels just as good as spiritual satisfaction and inspiration.  The calamitous prophesy of the fourth year fruits reminds us that just as a spiritual loss should be more painful than a material one, a material gain can’t compete with the spiritual.

This article appears in the September 22 2016 issue of the Jewish News.

Source: Rabbi Isaacs Blog

The talis, or talit (prayer shawl), with its tzizit fringe strings hanging down from its four corners, is one of the most well-known Jewish symbols.  In Biblical and Talmudic times, the talis looked considerably different.  Six of the eight strands were the natural off-white wool color, like all of the strands on ours.  Their remaining two strands were dyed with techeilet, a type of bright turquoise that made those two strings stand out starkly from the rest (the tradition of how to make the dye was then lost for centuries, but after extensive research it is now being revived).  Although the Torah itself doesn’t explain the purpose of these techeilet-colored strings, the sages of the Talmud do give an explanation.  They said that the techeilet thread is similar to the color of the sea, the sea to the sky, the sky to a sapphire stone, and a sapphire stone to the Almighty’s Throne of Glory (which is described in a verse in the book of Ezekiel as similar to a sapphire stone).  The idea is that no matter what one becomes preoccupied with in his mundane, day-to-day life, he will see the strings, and the techeilet in particular, and be reminded of the Almighty and spirituality.  But this explanation seems convoluted.  Why does the Torah decree a lengthy chain of items and phenomena to remind us, only eventually and in a roundabout way, of the Throne of Glory?  If the Torah wants people to recall and be mindful of that metaphoric Throne, it should cut out the seemingly unnecessary two intermediate steps.  There should be a few sapphire-colored tzitit strands which could directly remind one of the Throne of Glory.  Why does the Torah need the extra steps of the techeilet, the sea, the sky, and the sapphire stone?

In his book First Things First, Stephen Covey distinguishes between two approaches to change.  When a problem doesn’t need a long-term solution, like cramming for an exam, quick fixes can sometimes work.  But in a natural setting, as on a farm, there is no way to cheat the system.  If one is too lazy to plant in the spring and summer, there is no way to make up for lost time in the fall.  There will be nothing to harvest.  One can make the mistake of thinking that like passing a test, spirituality is attainable via shortcuts.

Rabbi Moshe Feinstein (1895 – 1986) suggests that the sequence of reminders from the techeilet to the Throne of Glory addresses methods of achieving personal growth and attaining spirituality.  In these areas, there are no quick fixes.  A person must ascend in gradual steps until he or she finally reaches the Throne – genuine spiritual connection and accomplishment.  If steps are omitted, the resulting shortcomings inevitably and eventually catch up with a person, and the result is frustration, despair, and setback.  True spiritual-religious achievements, much like muscle building, must be developed slowly and incrementally and cannot be pursued impulsively based on momentary inspiration.  They involve changing bad habits, developing good ones, and most important of all changing the way one thinks about oneself and the world.  A couch potato cannot get into shape by running all day right before a marathon.  Long-lasting spiritual depth can only be reached by slowly walking the road of toil and great effort; changes and attempts at growth that a person makes without walking that road will ultimately not last.  The message of techeilet is that like on the farm, true spiritual growth is not a sudden metamorphosis but rather a slow going and gradual evolution.

This article appears in the July 1 edition of Jewish News.

Source: Rabbi Isaacs Blog

Studying is Not Enough:  The beginning of Parashat Bechukotai describes the type of observance of the Torah that will result in meriting the great blessings listed subsequently.  “If ye walk in My statutes, and keep My commandments, and do them” (Leviticus 26:3).  The rabbis of the Midrash explain that since the second part of the verse is clearly talking about actually observing the commandments, “walk in My statues” refers to laboring in Torah study (see Rashi).  Is “laboring” in Torah study meant to be taken literally?  If it would merely be a poetic or rhetorical way of referring to Torah study, the Torah would already be expressing a sufficiently novel idea.  It would be saying that studying the Torah is just as important, valuable, or meritorious as actually doing the mitzvot and would therefore make the nation deserving of the blessings listed in the Parasha.  Another Midrash (Koheleth Rabbah), however, makes it clear that labor is indeed meant literally.  It states that the Almighty decreed that forgetfulness be part of human nature because if we would never forget, we could just study Torah and not need any labor.  Studying Torah is enough to learn facts and information.  To understand, to analyze and to integrate, one must labor.  This message seems especially important in our time.  One rabbi already remarked in the middle of the Twentieth Century – way before Google, Wikipedia, and Kindle – that people confuse research with deep analysis and thoughtful insight.  If we understand things too quickly because we have already imbibed all of the facts and information – if we think that merely knowing something is understanding it – we risk losing the critical ability to think with nuance and depth.

Supernatural Victory:  One of the blessings in the beginning of Parashat Bechukotai describes the military strength that the Jewish people can receive in a time of war.  “And five of you shall chase a hundred, and a hundred of you shall chase ten thousand; and your enemies shall fall before you by the sword” (Leviticus 26:8).  According to the usual rules of military engagement, the victorious side would need to have greater numbers in its army to chase away its enemy.  If it did not have the advantage of greater numbers, it could still potentially win if its army compensated by fighting with greater skill or strategy.  This would become less and less likely as the numeric disadvantage grew.  The blessing mentioned here promises that even when the Jews are severely lacking man power – the Torah’s example is even when there are twenty enemy soldiers for each Jewish soldier – the Almighty’s assistance will assure victory.  The second example the verse gives of an otherwise unlikely victory, however, is puzzling.  It says one hundred of us will be able to chase away ten thousand enemies.  According to the ratio of the first example, one hundred should only be able to chase away two thousand – each Jew would chase twenty enemies.  If we will be blessed with victory even when there are one hundred enemy soldiers for each Jewish soldier, why does the Torah even mention the smaller miracle of each person being able to disperse only twenty enemies?  Rashi, picking up on the inconsistent ratio, explains that it teaches the power of Jewish unity.  “The few that fulfill the Torah cannot be compared to the many that fulfill the Torah together.”  The Talmud comments that the load that one person can carry on his shoulder is only one third of what he can potentially carry together with a second person.  The colossal challenges that we face in our synagogues, communities, and as a nation require immense energy, insight, and resources.  To the extent that we are able to bear the load of these challenges together, the smaller and more manageable that load will become.

These thoughts are based on the classes of Rabbi Yeruchem Halevi Levovitz.  A version of this post appears in this week’s Jewish News.

Source: Rabbi Isaacs Blog

Due to the space limitations of a text message, please note that it is particularly important to read carefully, pay close attention to the context of the question, and use the answers as a springboard for further study.

If you would like my phone number to submit questions, please leave a comment and I will send it to you.

Q:  The OU Passover Guide has a list of Almond milk with OU non-Passover certification that they say can be used on Pesach for infants and those that are ill.  Why can’t healthy adults use them?

A: On page 100 of the 2016 OU Passover Guide it says that the products may contain kitniyot.  Almonds are not kitniyot and if the Almond milks had even a 49% kitniyot content, the kitniyot would be considered to be nullified and the product could be used on Pesach by anyone.  It also says that some of the products may contain minor ingredients that are possibly, though unlikely, produced from chametz-based raw materials.  This is a more serious concern.  However, due to the following factors, it is difficult to understand why the Almond milk would only be permitted to infants and those that are ill (at the very least, if purchased before Passover).  If it is unlikely that these minor ingredients are produced from chametz-based raw materials, it would seem that one could rely on the majority and assume that they are permitted in the first place.  Even if they are actually chametz-based, chametz is nullified before Passover with a ratio of 1:60, and although Ashkenazim are strict to say that nullification is reversed once Pesach begins (“chozer v’neior) it would not apply in this case since the components are indistinguishable from one another (Rama 447:4).  Perhaps the OU’s position is based on policy rather than letter-of-the-law halacha (they may only give a full Pesach endorsement to products that they have determined with 100% certainty to be free of any chametz/kosher concerns even if the product is halachically permitted, but they are nevertheless willing to give a limited endorsement in certain situations).

Q: Why do dried dates need a special Kosher for Passover certification?

A: They are often sprayed with dextrose, a type of sugar – which requires Passover supervision (Shulchan Halevi p 107).

Q: Do vitamins have to be kosher for Passover?

A: Although the strict opinions on this issue are prevalent, the basic halacha is that if you can’t get a kosher/kosher for Passover version of a particular vitamin, as long as they are swallow-able they are OK.

Q: My family gets really hungry at the Seder.  What is the earliest time I can start?

A: In normal circumstances, one may not make kiddush on the first two nights of Pesach until nightfall (i.e. the same time Shabbat is over) since Kiddush has to be made during the time that one may fulfill the mitzvah of eating matzah, and that mitzvah doesn’t commence until nightfall (like its partner mitzvah of the Pesach offering).  Additionally, all of the four cups (one of which is the Kiddush cup) must be consumed at night (Shulchan Aruch 472 with MB).

Q: Since Sefirah is coming, I want to get my haircut before Passover at the latest possible time.  When is that?

A: Due to halachic noon (midpoint of the day between sunrise and sunset) on Erev Pesach being the earliest time to bring the Pesach offering in the time of the Beit Hamikdash, that time and later is treated with a quasi  Chol Hamoed status.  Therefore a Jew may not cut hair after halachic noon but one may still get a haircut from a Non-Jew as long as Yom tov has not yet begun (Shulchan Aruch 468 and MB).  The same would apply to trimming one’s beard or shaving with an electric razor (but it’s possible that shaving would be permitted even after halachic noon according to those that permit it on Chol Hamoed).

Q: I washed and cut the tops off of strawberries using a chametz knife (all cold and clean). I have extras and want to freeze them. What is the status of the strawberries? Are they considered chametz or can I use them on Pesach?

A: A chametz knife can only transfer its status to food in three ways.  1. There is chametz adhered to it which transfers to the food; even if it is clean 2. if it is hot it will transfer chametz flavor which is absorbed into the knife; 3. even if it is cool and clean nevertheless if it is used to slice a sharp food like raw onions.  In this case, 2 and 3 do not apply, the only possibility would be 1.  Ideally, since we are generally strict about questions of chametz on Pesach and especially in this case when there’s no financial loss involved since you can save the strawberries for after Pesach, you should buy new strawberries for Pesach.  If you know that the knife and cutting board were spotlessly clean, then it would technically be permitted but as a precaution the strawberries should be thoroughly washed.

Source: Rabbi Isaacs Blog

Due to the space limitations of a text message, please note that it is particularly important to read carefully, pay close attention to the context of the question, and use the answers as a springboard for further study.

If you would like my phone number to submit questions, please leave a comment and I will send it to you.

Q: Does it matter what order I eat foods with different brachot?

A: If you want to eat a particular one first, then you do so no matter which bracha it is, and you have in mind that the bracha should apply to all of the foods you plan to eat with that same bracha. On the remaining foods if one has no preference, (or if one has no preference initially), one should follow this order: Hamotzee on bread; mezonot on cake/other foods made by baking flour; mezonot on cooked grains/flour (pasta, oatmeal); mezonot on rice; Haeitz on 7 species fruit; Haeitz on other fruits; Haadama on vegetables (or fruits that require Haadama like strawberries or bananas); Shehakol on liquids; Shehakol on beverages. So for example if you are eating mushrooms and drinking snapple, and you don’t have a preference, you make Shehakol on the mushrooms with intention that it should cover the Snapple rather than vice versa.  If you want to eat pineapple (Haadama) and blueberries (Haeitz), you would make the Haeitz first on the blueberries and then Haadama on the pineapple. This is all summarized very well in Guide to Halachos by Nachman Schachter.

Q: Is singing zemirot mandatory on Shabbos?

A: It is part of enjoyment of Shabbos which is a Mitzvah but the way you choose to fulfill that Mitzvah is your personal choice

Q: Someone told me that dried figs must be cut open and checked for insects individually.  Is that true, it seems like a lot of work?

A: They just need to be examined to make sure they are not obviously infested (cRc).

Source: Rabbi Isaacs Blog

Due to the space limitations of a text message, please note that it is particularly important to read carefully, pay close attention to the context of the question, and use the answers as a springboard for further study.

If you would like my phone number to submit questions, please leave a comment and I will send it to you.

Source: Rabbi Isaacs Blog

Due to the space limitations of a text message, please note that it is particularly important to read carefully, pay close attention to the context of the question, and use the answers as a springboard for further study.

If you would like my phone number to submit questions, please leave a comment and I will send it to you.

Q: Are there any requirements other than listening to the megillah reading on Purim night?

A: The night of Purim should have a festive atmosphere, and one should have a festive dinner by adding special food in honor of the holiday (but bread is not required like a typical Shabbat or holiday meal).  In addition it is customary to eat legumes like beans and rice or seeds since that’s what Esther did to maintain observance of Kashrut while she lived in the palace of Achashveirosh.  (S.A. 696)

Q:  Is there a specific time of day that I am required to eat my daytime Purim seudah (festive meal)?

A:  Beginning of Seudah:  It is best to eat it in the afternoon, after one has already davened Mincha, but one may have it any time of day if necessary.  End of Seudah:  The majority of the meal should be finished before the end of the day. (S.A. 695)

Q: I have dairy silverware from my grandparents that hasn’t been used in about 50 years.  Can I kasher it and use it for meat?

A: Normally to prevent confusion in the kitchen we customarily do not change the status of a utensil from meat to dairy or vice versa.  In this situation it is permitted to kasher it from milchig (dairy) to fleishig (meat) (or vice versa) since it is more than year since it was used and since some opinions hold that all utensil absorption is diminished after that amount of time has elapsed and may be used for fleishig even without kashering.

Q:  To you have to tovel (immerse in a mikvah) the cup of a new blender in the mikvah since the blade is metal?

A: Yes, since the blender is often used with food that is ready to eat.

Q:  (I have a hunch about the answer to this but…) what happens if a fleishig glazed earthenware coffeee mug was placed in a dairy microwave to boil water for coffee and then milk was added while the contents were yad soledes bo (greater than 160 F)?

A: As long as the mug hasn’t been used in the last 24 hours and was clean, the coffee is permitted.  Regarding the mug, earthenware cannot be kashered because it is assumed to be a one-way street – it absorbs but cannot be purged like metal and some other materials.  Even though this mug is glazed, most authorities are nevertheless of the opinion that is no-longer kosher, since the glaze does not prevent milk absorption into the earthenware interior which would then become non-kosher when the two absorptions intermingle.  If it is a special situation there is room to be lenient.

Q: Can you kasher Corelle?

A: Corelle is considered like any other glass: it cannot be kashered for Pesach, but it can be kashered if it becomes non-kosher.

Source: Rabbi Isaacs Blog