Learning Before the Seder: Kashering Your Kitchen

Ceramic dishes that have been used for hametz the whole year, even if they were used for oats or other grains, should be wiped well such that there is no noticeable hametz left, and then it is permitted to keep them until after Passover and use them either for what they were used for before Passover or something different. They should be hidden on Passover in a hidden place where one does not normally go, lest one come to use them on Passover. It is good to close them in a room and to hide the key. But refiring it in fire does not work for any ceramic item that was used for hot things, even if it was not used on the fire and boiling liquid was just poured into it. Rem"a: There are those who forbid even for the second container (the Magid chapter 5). Even if they are filled with coals, we are concerned that he will be worried that the containers will crack (meaning that they will break) and will not do a complete refiring. However, if he returns them to the furnace where they make new ceramic items, it is permitted. Because they are sent into a big fire like this, clearly he will not be concerned that they will break. But this is not true of our ovens. Rem"a: For every object that needs to be made white-hot or scalding, it is forbidden to use it even for cold things without kashering it (Mordechai at the beginning of Chapter Kol Shaah). See in Yoreh Deah Chapter 421.

An earthenware roasting pan on which loaves of chametz are baked during the entire year should not be used to bake matzah on Pesach. If it was filled with coals and kindled on the place where chametz was cooked, matzah it is permitted to be cooked on it.

And Shmuel said: They need not be broken. Rather, he should retain them until after its time, i.e., the conclusion of Passover, and then he may prepare food of either the same type or another type in them.

A tripod needs heating - this is a three-legged utensil. When it's used to stand something over a flame, like a pot or a dish in the oven, during the year, and then one wishes to use it on Pesach, one needs to heat it in a flame, since sometimes dough is spilt on it. The tripod then absorbs leaven taste, by means of the flame. And this is only "from the outset", and out of the strictness of leaven -- since in truth, two pots that touch one another don't have any taste transfer, as was explained in Yoreh Deah 92:7. And there's other support for this viewpoint, as even if one spills on it, this is burnt up and leaves, because it's always in the flame. And therefore, certainly "light heating" suffices, and after the fact if it was used without heating at all(!), even this we do not forbid.

It is also important to know that throughout the year one should be stringent and refrain from eating food that has fallen onto the enamel cook top under the grates, because meat and dairy foods spill there, and the enamel becomes not kosher. If one knows that the enamel has been cleaned thoroughly and that no meat and dairy foods have spilled on it in the past twenty-four hours, one may eat what falls there. But when these two conditions have not been met, one should be stringent and refrain from eating whatever comes into contact with this enamel, because it might have absorbed the taste of meat and milk. If a thick piece of food falls there, one may cut off the side that has come into contact with the enamel and eat the rest.

Objects used on the fire, like skewers and gridirons and similar things, need to be made white-hot (libun). Libun is such that there are sparks on them. Rem"a: Some are lenient if it is hot such that straw burns on it from the outside (Mordechai the end of Avoda Zara and Hagahot Maimoni chapter 17 from the Laws of Forbidden Foods). We follow the first opinion for everything that requires libun, but for something that needs scouring but has cracks or we are stringent to make it white-hot, it is sufficient to do this lesser libun. A tripod needs libun (Mahari"l).

§ Returning to the mishna, the Gemara asks: And how much does one heat utensils to make them white-hot? Rabbi Mani says: Until they shed their outer layer. And how does one purge utensils with boiling water? Rav Huna says: One immerses a small kettle inside a large kettle of boiling water.

Clay barrels in which barley beer is stored are permitted through scouring or by pouring for three days. Rem"a: Scouring the barrels should be done thus: stones should be made white-hot and put inside. Boiling water is poured from a first container. The barrel is rolled such that the scouring gets to every part (Hagahot Maimoni chapter 5). After the fact, if wine or honey was put inside without scouring, but [the barrel] was cleaned well, it is permitted to drink from it on Passover (Mordechai chapter Kol Sha'ah and Hagahot Oshr"i chapter 2 of Avoda Zara and Trumat HaDeshen in chapter 201).

One who takes old (ie used) vessels from one who worships idols [lit. stars] - the way in which the idol-worshipper used them, this is how he kashers them. Therefore, one who takes a used old vessel which was used for cold, such as cups and plates and others like that - he washes them and he must scrub them well in water at the time of washing in order to remove and polish the issur (forbidden matter) which is on them, and afterwards rinse them in water and dip them (in a mikvah). GLOSS: There are places where the custom is to permit placing wine in vessels (ie barrels) where the planks of wood are smeared with fat because the nature of wine is to separate itself from the fat, and the fat congeals and stands by itself and does not touch the wine at all (Ribash 149). [He] took from them [the idol-worshipper] vessels which were used with heat, whether they were made of metal, wood or stone, he dunks them in boiling hot water and afterwards dips them in a mikveh (if they are made of metal) and then they and are permitted. If you dipped them [ie metal vessels] in a mikveh [first] and then dunked them in boiling hot water - they are permitted. And there are those who say that they must be dipped in the mikvah again. GLOSS: This is also the rule regarding a vessel made of bones, see the laws of Passover 451. One should not dunk a vessel in boiling water when the vessel has been used within the past 24 hours (see the Tur) and one should not use the water from the boiling (Aruch). Every instance in which dunking in boiling water is required it doesn't help if you scrape them with a tool. And see above 108: The Law of a Bread Paddel which is Issur. The laws of [making kosher through] boiling and heating until it turns white are written in the Laws of Passover.

All items, even ceramic ones, that were used for cold hametz are permitted to be used for even hot matzo, besides for the yeast or charoset containers. Even though these have only been used for cold hametz, it is forbidden to use them for hot matzah, but it is permitted to put in cold, baked matzah, but it is forbidden to use them to knead. This is all without scouring, but after scouring, even the yeast or charoset containers can be used if they are not ceramic. If they are ceramic, scouring does not work; even if they have only been used for cold hametz, they cannot be used for even cold matzah. Today, the practice is to not use old earthen jars on Passover (meaning old ceramic things). (The winter house-oven is treated like a ceramic object, and it is forbidden to put anything on the oven on Passover) (Mahar"i Weil).

All earthenware vessels that were used for chametz while cold may be used for matzah while cold, except for the utensils in which yeast and charoset were placed, for their leavening effect is powerful. Similarly, a kneading trough in which chametz is kneaded and left to become leavened is considered as a place where yeast is soaked, and we do not use it on Pesach.

An olive-worth of meat that falls into a pot of boiling milk: let a non-Jew taste the dish. If he says that there is a taste of meat in it, it is forbidden. If not, it [the milk] is permitted, even in less than sixty, and that piece [the meat] is forbidden. When is this true? When one quickly removes the piece before it exudes the milk that it absorbed, meaning before the pot rests from its boiling. But if he didn't remove it before it was able to exude the milk it absorbed, even if a non Jew tastes it and it has no taste at all, (Rama) it's forbidden unless there is sixty. See chapter 98 (Shulchan Arukh, Yoreh De'ah 98) that we aren't accustomed to rely on the tasting of a non-Jew and we need sixty every time.

The same laws apply with regard to a piece of meat [cooked] with milk or an ordinary animal that was slaughtered in the Temple courtyard, for it is forbidden to benefit from [the latter] according to Rabbinic decree, as will be explained in Hilchot Shechitah. Even the slightest amount of them causes [a mixture] to become forbidden until they are removed.
Similarly, when a gid hanesheh was cooked with other similar tissue or with meat, when it can be recognized, it should be removed and the remainder is permitted. For giddim do not impart flavor. If one cannot recognize it, the entire mixture is forbidden. For [the gid hanesheh is considered as a created being in its own right. Hence, it is significant; no matter how small it is, it causes [a mixture] to become forbidden.