Silver goblets:It is proper, le-khatĥila, to perform hagala on silver goblets used for kiddush wine and other hard drinks, because crumbs sometimes fall into the goblet along with these strong drinks, which, according to some poskim, causes their taste to be absorbed into the goblet after eighteen minutes (as explained above 10:14).
Plastic baby bottles:It is better to replace them because they absorb tastes at a level of irui from a kli rishon. When necessary, one may clean them and perform hagala.
Electric water heaters, urns, samovars, and hot water kettles must undergo hagala, because ĥametz crumbs may have fallen into them, causing their taste to be absorbed. Hagala in this case means filling the device to the top with water, boiling it, and then pouring it out through the opening generally used to dispense the water. Before hagala, it is good to clean out the stone deposits that accumulated inside. If one puts challah loaves on the lid of the urn to warm them before the Shabbat meal, hagala should be performed on the kettle and its lid. 9
Thermos:After cleaning it properly, hagala should be performed on it. If this is difficult, pouring boiling water into it and around its opening is sufficient.
Toaster:This requires heavy libun, and since it is liable to be damaged in the process, it should not be koshered.
Kneading Utensils:Rema maintains that such utensils le-khatĥila require light libun, but since they are likely to be damaged, they should not be koshered (451:16, 17). According to Shulĥan Arukh, it is possible to kosher them via hagala. Le-khatĥila, the custom is to be stringent, in keeping with Rema’s ruling (Kaf Ha-ĥayim 451:196, 263).
False Teeth:These should be cleaned thoroughly before the onset of the ĥametz prohibition. They need not undergo hagala, because people do not normally put boiling foods or liquids in their mouths; just as they are used for both meat and dairy when cleaned in between, so can they be used on Pesaĥ. Some believe that due to the gravity of the ĥametz prohibition, they must be koshered in a kli rishon or kli sheni. 10
13. Earthenware and Porcelain Utensils
If earthenware absorbs ĥametz hot, even via a kli sheni, hagala is not effective. Although libun would effectively burn the taste absorbed in the utensil, the Sages forbid koshering earthenware utensils through libun because there is concern that they will crack (see above 10:7). If used cold, however, one may kosher them by washing them thoroughly. If a ĥametz beverage was allowed to sit in such a vessel for twenty-four hours, one may kosher it by soaking it in water for three consecutive days (ibid. 14).
China, clay, and ceramic utensils are considered earthenware.
Regarding porcelain which, though made like earthenware, has a smooth surface like glass, most poskim maintain that it has the status of earthenware, and there is no way to kosher it. This is the halakha (MB 451:163; Kaf Ha-ĥayim ibid. 305). However, some poskim believe that since the surface of porcelain is smooth like glass, it does not absorb at all. When there are additional doubts, their lenient opinion is taken into account. 11
Leading Rishonim take diametrically opposed positions regarding the status of glass utensils.
According to Rabbeinu Tam, Rosh, Rashba, Ran, and many others, glass is smooth and hard, and even if it had been used to hold boiling hot foods, it does not absorb their tastes. Therefore, even if glass utensils were used with boiling-hot ĥametz throughout the year, they may be rinsed thoroughly and used on Pesaĥ. This is the position adopted in SA 451:26. Similarly, glass utensils may be used alternately for hot meat and hot dairy foods, as long as they are cleaned well in between.
According to Smag, Smak, Mordechai, Agur, and Terumat Ha-deshen, glass, because it is made of sand, has the status of earthenware, which is also made of sand and which absorbs tastes but does not release them. Therefore, if one uses glass utensils with hot ĥametz foods, there is no way to kosher them for Pesaĥ. This is the position adopted by Rema.
There is also a third position, which maintains that glass utensils have the same status as metal utensils, which can absorb and release when boiling hot. However, since glass utensils are fragile and liable to break during hagala, there is no way to kosher them for Pesaĥ (Or Zaru’a, Shibolei Ha-leket).
In practice, many Sephardim follow Shulĥan Arukh’s opinion that glass utensils do not absorb and thus may be rinsed thoroughly and used on Pesaĥ. However, there are important Sephardic authorities who are stringent in this regard, Ben Ish Ĥai among them (Year One, Tzav 14).
In Ashkenazic communities, some follow Rema’s stringent ruling while others adopt the middle opinion, allowing glass to be koshered via hagala on the grounds that today’s glass is stronger than in the past and capable of enduring hagala. There is even more of a tendency to be lenient with tempered glass cookware (like Pyrex), which is fire resistant. Some rule that hagala should be performed three times on glassware.
In practice, Ashkenazic Jews do not kosher glass utensils for Pesaĥ through hagala, in keeping with Rema, and only under pressing circumstances rely upon the lenient position. With regard to prohibitions other than ĥametz, the tendency is to rely upon the lenient poskim, waiting twenty-four hours from when the utensil last contained hot food and performing hagala three times. 12
Enamel utensils are made of metal and coated with a thin layer of enamel for aesthetic reasons. The inside of the pot is usually colored white, while the outside is decorated with different colors. Enamel is made of sand like glassware, but it is processed differently. Great uncertainty arose regarding such utensils. At first, poskim were uncertain because the craftsmen kept enamel’s composition secret. Then, when it became known that enamel is made of sand, uncertainly arose again as to whether such utensils have the status of earthenware.
In practice, the poskim rule that one may perform hagala on enamel utensils like all other metal utensils, and some recommend performing hagala three times. Yet regarding Pesaĥ, some instruct not to perform hagala on enamel utensils in light of the severity of the ĥametz prohibition. 13
Plastic utensils that have absorbed the taste of boiling hot food are koshered via hagala with boiling water, like all other utensils. This is true of all types of metal, such as silver, copper, iron, aluminum, etc., as well as utensils of leather, wood, and bone. It is earthenware alone that the poskim say cannot be koshered, because, due to its unique composition, it is very absorbent, but does not release all that it absorbs. And some poskim say that glassware has the same status as earthenware.
However, Igrot Moshe (OĤ 1:92) states that one should not perform hagala on utensils made of plastic or other synthetic materials not mentioned by the Rishonim, since such materials might be like earthenware, which does not release what it has absorbed. Nonetheless, the overwhelming majority of Aĥaronim agree that hagala is effective on plastic utensils, and this is the halakha. Utensils made of hard plastic are koshered through hagala in a kli rishon on the flame, whereas plastic utensils that are liable to be damaged in a kli rishon on the burner can be koshered at the same level they absorbed the ĥametz. 14
^ 9.. This matter is unclear. Since there is no liquid present and the challah reached the temperature of yad soledet, perhaps it should be considered to have absorbed the taste of challah as though by means of direct fire, meaning that the lid would need heavy libun – a process that it certainly will not be able to withstand. On the other hand, since there is no liquid present the taste of the challah may not become absorbed into the lid at all, just as taste does not pass between two dry pieces of metal. The custom is to be lenient, especially once factoring in the opinion that ĥametz throughout the year has the status of "heteira," and thus hagala is effective where normally libun would be (see above 10:6) and that once twenty-four hours passed since its use, it becomes a doubt relating to a rabbinic law. However, since there was definitely ĥametz on the urn, the lid should undergo hagala in boiling water.
^ 10.. Among the lenient opinions are: Responsa Beit Yitzĥak YD 1:43:12, Melamed Le-ho’il OĤ 93, R. Zvi Pesaĥ Frank, and Yabi’a Omer 3:24. Responsa Maharsham 1:192 is lenient regarding meat and dairy but is stringent vis-à-vis Pesaĥ, insisting that they be koshered by irui of boiling water. Tzitz Eliezer 9:25 states that technically one need only scrub them well, but there are stringent opinions that insist on performing hagala in either a kli rishon or kli sheini.
^ 11.. Shiyarei Knesset Ha-gedola OĤ 451, Hagahot Beit Yosef 30 states that the universal custom is to use porcelain on Pesaĥ even if it was used for ĥametz throughout the year, since porcelain is like glass which does not absorb. He was stringent for himself, as per the opinion of Radbaz, but did not rule stringently for others. She’elat Yaavetz 1:67 also permits it. Pri Ĥadash states that one may only be lenient if he has authentic porcelain, but nowadays, since there is much counterfeit porcelain, all agree that one must be stringent. This is also the opinion of Maĥzik Berakha 451:10, as quoted in Kaf Ha-ĥayim 451:305, and Kol Mevasser 1:80. This is the accepted custom. However, one may be lenient if there are other doubts, as explained by the Aĥaronim cited in Hagalat Kelim 13:368 and Yabi’a Omer YD 1:6 and 7:10.
When porcelain breaks, one can see that its inner texture is coarse, like earthenware, and its outer texture is smooth. There are also porcelain utensils that are smooth on the inside and coarse on the outside. It seems that if a utensil like this absorbed in its coarse area, everyone would agree that it has the status of earthenware. Nowadays, most dishes are made of tempered glass, which is sand-based and has a hard texture like glass, even though it is not always smooth as glass. I am often asked whether such dishes can be koshered via hagala if they were used for non-kosher or for milk and meat. In my humble opinion, these dishes should be considered like glass, since when they break one can see that they are made of dense material – like glass, not like porcelain. They thus have the status of quality glass utensils that can withstand the hagala process, as will be explained in the next section. Even the Ashkenazic custom is to be lenient when necessary to kosher such a utensil from forbidden taste it absorbed. To dispel all doubt, one should kosher the utensil with hagala three times (it is not necessary to use three separate refills of water), since according to Itur this would even work for earthenware. It seems that even according to the custom of SA glassware does not need to be koshered, since today’s dishes are not so smooth that they should undergo triple hagala. (I have not mentioned any particular brand names since companies constantly change the composition of their products; I have referred specifically to utensils whose hard texture is similar to that of glass.)
^ 12.. Among Ashkenazic poskim who permit hagala on glassware if there is no concern that it will break are: R. Shlomo Kluger in Responsa Tuv Ta’am Va-da’at, third edition 2:25 and Responsa Maharam Schick YD 141. Tzitz Eliezer 9:26 leans toward permitting one to kosher glassware via hagala and quotes R. Zvi Pesaĥ Frank that one may kosher tempered glass cookware for Pesaĥ, but should do so via triple hagala, since according to Itur triple hagala works even for earthenware vessels if twenty-four hours have elapsed since their last use. According to these poskim, even those who adopt SA’s lenient ruling vis-à-vis glassware would agree that any glassware strong enough to withstand the heat of a kli rishon must be koshered via hagala, out of concern that these utensils may have absorbed taste at such high temperatures. This is the opinion of Responsa Yaskil Avdi 4:14. See also Hagalat Kelim 13:59 for a detailed list of the opinions regarding glassware and 13:375 for the opinions about tempered glass cookware.
^ 13.. Responsa Ĥatam Sofer YD 113 states that enamel is koshered via light libun. R. Shlomo Kluger rules stringently that one may not kosher enamel even via libun, since it might get damaged in the process (Tuv Ta’am Va-da’at, first edition §183). Ktav Sofer YD 78 permits koshering enamel via triple hagala. SHT 451:191 quotes Ĥatam Sofer and then states that many great authorities were more stringent in this matter when it came to Pesaĥ. This is also the view of Maharsham 1:53. Aderet rules that one may kosher such utensils via hagala, but out of respect for Ĥatam Sofer states that one should use triple hagala (which according to Itur works even for earthenware vessels once twenty-four hours have elapsed since they were last used). This is also the opinion of AHS YD 121:27. R. Mordechai Eliyahu states that one may kosher these utensils for Pesaĥ via hagala, and preferably triple hagala.
^ 14.. Those who ruled leniently are: Responsa Ĥelkat Yaakov 2:163, Seridei Esh 2:160, Tzitz Eliezer 4:6, and many others. This is also what Hagalat Kelim states in 13:91. Sidur Pesaĥ Ke-hilkhato 9:25 assigns greater weight to the stringent opinions, and states that triple hagala seemingly works according to everyone (based on the opinion of Itur that triple hagala is effective even on earthenware vessels once twenty-four hours have elapsed since their last use, although it seems that one needs to change the water between each stage of hagala; see Sidur Pesaĥ Ke-hilkhato 9:25 n. 10). It seems proper to wait twenty-four hours, ensuring that any absorbed taste is foul, in which case hagala is only rabbinically required, and one may be lenient in a case of uncertainty about a rabbinic law.