Kashering for Pesach-Halachic digest & Guideline

*The article below is an excerpt from the above Sefer

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The laws of Kashering vessels are complex and hence it should only be done by one which is expert in these laws.

One must be aware of the following details:

  1. Is the vessel made of a Kasherable material?
  2. How has the vessel been used? What form of Kashering is required for it? Libun? Hagalah?
  3. What must one do if the vessel is rusty?
  4. How does one do Libun?
  5. How does one do Hagalah?
  6. May the vessel be Ben Yomo?
  7. Must the vessel one is Kashering in be itself Kashered?
  8. How long must the vessels remain in the water by Hagalah?
  9. May many vessels be Kashered simultaneously?
  10. May one Kasher on Erev Pesach or Pesach?

A. What to do with Chametz vessels that one does not plan to Kasher:

  • Cleaning: All Chametz vessels which one does not desire to Kasher for Pesach, or is unable to Kasher them, are to be cleaned from Chametz. One is to scrub them and slightly rinse them down from any recognizable Chametz.
  • Putting them away: One is to hide the vessels in an area which he is not accustomed to enter into throughout the entire Pesach. Furthermore, it is proper to place the vessels in a room [or closet] which will be locked, and then hide the keys, in order to prevent any possibility of entering there during Pesach. Those which are accustomed to place the vessels in a very high area which is visible, have upon what to rely, although one who is stringent to hide them away from sight will be blessed.
  • Un-cleanable Chametz vessels: All vessels that are difficult to clean from Chametz are to be sold to a gentile and stored away as written above.


B. Kashering new vessels:

  • New vessels which are bought from a gentile do not need to be Kashered. Hence, all vessels which appear new may be bought from a gentile store or company. However, vessels sold by a gentile individual from his home are not to be purchased.
  • Do new pots and pans need to be Kashered today due to suspicion of them having been smeared with non-Kosher fats?
  • Many Poskim rule there is no need to Kasher new pots or aluminum which had non-kosher fats smeared on them during manufacturing. However, some are accustomed to be stringent. Practically, the worldwide custom is to not require them to be Kashered. However, in certain areas, such as Eretz Yisrael, many are accustomed to do so.

C. Forms of Kashering:

  • The Torah taught us a great rule “Kebolo Kach Polto”; the same way the Issur entered that is the way it is removed. There are a thus number of different forms of Kashering that are done to Kasher a vessel. How each vessel is to be Kashered, and what level of Kashering it needs, is determined based on its past use.
  • The following are the different levels:
    1. Libun Chamor
    2. Libun Kal
    3. Hagalah
    4. Iruiy with Even Meluban
    5. Hadacha


Libun Chamor/Gamur:

  • Libun Chamor [also called Libbun Gamur] is defined as torching the vessel until sparks fly from it or alternatively, until a sheet of its metal peels off.


Libun Kal:

  • Libun Kal is defined as torching the vessel until its opposite side becomes Yad Soledes. When burning Chametz from a rusty area or crack the custom is to do so until the point that a piece of straw would burn if it were to be placed on other side.



  • Hagalah is defined as entering the vessel into a pot of boiling water.


Iruiy with Even Meluban:

  • Iruiy with Even Meluban refers to pouring hot water from a Keli Rishon onto the item and then passing throughout the entire item a red-hot stone or metal, hence causing the water to boil.
  • Using an iron: A hot iron which causes the water to boil may be used as an Even Meluban. Hence when Kashering through Iruiy with Even Meluban one is to pour hot water onto the item and then pass the hot iron throughout the entire surface of that item, hence causing the water to boil. When doing so one must observe when the iron has lost its power of heat to be able to boil the water, and consequently reheat the iron to its boiling power.
  • Using a water boiler “Kumkum”: Water which is poured from a mini water boiler [“Kumkum”], while the boiler is still on and the water is boiling, is considered like both Iruiy and Even Meluban, and hence when pouring from such a vessel there is no need to pass over the surface using a red hot stone or metal.



  • This refers to Kashering through cleaning the vessel very well with even cold water.


D. What form of Kashering does a vessel require-General rules?

  • *The below list only refers to the form of Kashering required for vessels made of Kasherbale materials. For a list of those materials that are Kasherable and those materials that are not Kasherable-see Halacha E! For a list of vessels and their specific Kashering Laws see Halacha F!
  • Chametz cooked in liquid in the vessel: All Kasherable material vessels that had Chametz cooked with liquids require Hagalah or Libun Kal.
  • Chametz baked without liquid in the vessel: All Kasherable material vessels that had Chametz baked in them [without liquids] require Libun Chamur.
  • Chametz soaked in the vessel: All Kasherable vessels which had Chametz soaked in liquid for 24 hours require Hagalah or Libun Kal.
  • Do pots which are used to cook in have the status of absorbing food through liquid, or the status of absorbing food directly? All pots that had food cooked inside with liquid have the status of absorbing food through liquid, even if the food burnt inside the pot, and thus it does not require Libun Chamur, as there is always some liquid found on the bottom of the pot.

E. What materials may be Kashered?

  • Earthenware pottery: Can only be koshered through placing it in an oven and heating it to the point that it can be reformed. Even if an earthenware dish was used for only cold Chametz, one should not place even cold Pesach foods on it. An earthenware oven can be Kashered through Libun Gamur. Examples of earthenware vessels that cannot be Kashered: Crockpot; Mugs.
  • Sundried clay vessels: Vessels made of sun dried, is Kasherable.
  • Wood vessels: Is Kasherable so long as it does not contain cracks and the like. The custom is to Lechatchilah never use any wooden vessels which were used for flour consistently, even if one cleaned it and performed Hagalah. All wooden vessels may be sanded down and koshered.
  • Metal vessels: Are Kasherable. If the vessel absorbed the food through cooking in water, then it suffices for it to be heated to the point that its outside reaches the point of “Yad Soledes Bo”. This can be done by either using a torch [Libun Kal] or dipping it in boiling water [Hagalah]. If the vessel absorbed the food directly, without any liquid then it requires “Libun Gamur, which means that it must be heated until sparks begin to fly off from it, or until a layer of it peels off. This applies even Bedieved.
  • Glass vessels: The custom amongst Ashkenazic Jewry is not to Kasher for Pesach any glass vessels which have suspicion they may have absorbed Chametz. These vessels are not to be used for Pesach, and are rather to be put away with the Chametz vessels. [Sefardim however are lenient to allow using glass vessels even without Hagalah, so long as they have been washed and cleaned.]
  • Glass coated vessels: If the vessel is coated with glass on its inside, in the area where the food is placed, then it may not be Kashered. If it is coated with glass only on its outside, then if it is never commonly placed directly over a fire to cook in, such as silver vessels coated externally with glass, then it may be Kashered through Hagallah. If however it is not uncommon to use it to cook with over a fire, or even to occasionally heat food in it over a fire, then it may not be Kashered.
  • A vessel placed together using glue: Hagalah is invalid for such a vessel as the heat can easily ruin it and there is thus suspicion that to prevent this one will not heat the water enough for the Hagalah.
  • See the chart below for all of the following materials: Ceramic; Enamel; Marble; Plastic; Porcelain; Pyrex; Teflon.


F. Practical list of items:

List of vessels and their Kashering status

Vessel Law
Aluminum Kasherable based on use
Baking Pan Libun Chamor They are thus not Kasherable.
Burners of stove top Libun Chamor
Ceramic Cannot be Kashered
China Cannot be Kashered
Counter Iruiy Keli Rishon with Even Meluban
Cups Cannot be Kashered unless made of metal, in which case needs Hagalah
Earthenware Cannot be Kashered
Enamel Custom is not to Kasher for Pesach
Frying pan If coated with enamel/Teflon may not be Kashered. If not coated may be Kashered based on use.
Glass Cannot be Kashered
Grates of stove top Libun Chamur
Grinder Hagalah
Marble Hagalah
Oven Libun Chamur
Kiddush Cup [silver or metal] Hagalah
Knives Best not to Kasher for Pesach; if Kasher needs sharpening and Hagalah
Plastic Dispute amongst Poskim if may be Kashered.
Pot [not coated with enamel] Hagalah
Porcelain Cannot be Kashered
Pyrex Dispute amongst Poskim if may be Kashered.
Silverware Hagalah
Sink spout Clean and wash
Sink [made of enamel/ceramic/glass/plastic] Cannot be Kashered
Sink [made of metal] Iruiy with even Meluban
Skewer for barbecue Libun Gamor
Steel [including stainless steel] Kasherable based on use
Stove top [enamel] Cannot be Kashered
Stove top [stainless steel] Iruiy Keli Rishon with Even Meluban
Teflon Cannot be Kashered
Toaster Oven Do not Kasher. Sell to gentile and put away
Wood [without cracks] Hagalah
Wood [with cracks] Cannot be Kashered

Pots, Cutlery and Kitchenware


  • All forks, spoons and other cutlery made of Kasherable material, such as silver or stainless steel, is to be Kashered through Hagalah.



  • It is a Mitzvah Min Hamuvchar for all those which have the capability of doing so, to buy new knives for Pesach. However, from the letter of the law doing Hagalah to them does suffice [and one may certainly rely on this if it is not so feasible for him to get new knives.] One must sharpen the blade prior to doing Hagalah in order to remove any rust the blade may contain. If the knife contains a handle and the blade is inserted into the handle, then it cannot be koshered due to the inability to remove any Chametz from in between the crevices. Likewise, if the blade is attached to the handle with glue it cannot be Kashered.


  • The custom is to Kasher cups through Hagalah. If one used the cup for a hot Pesach drink without previously Kashering it, the drink remains Kosher.
  • Glass cups: Are not Kasherable.
  • May one Kasher a Kiddush cup that contains an upper lip? Yes, as the lip is external and there is thus no worry that Chametz entered inside.



  • Whether or not a pot may be Kashered is dependent on the material that it contains of-See previous Halacha E! If the pot is made of a Kasherable material, such as metal without a Teflon coating, then if it is used for cooking with liquid it requires Hagalah.
  • Teflon/Enamel: If coated with enamel/Teflon then it may not be Kashered.
  • Do the handles of pots and pans need to be Kashered? From the letter of the law, they do not need to be Kashered and certainly one need not worry of the cracks that they contain [which may have food on them]. Nevertheless, one should clean it and do Hagalah to it, or do Iruiy Keli Rishon without needing a stone.
  • Do pot covers need Hagalah?


Frying pans and all pots used for frying:

  • If one used this pot to fry the food with a nice amount of oil, then by Kashering for Pesach the pan needs Hagalah. If, however, one fried food in it using very little oil, just enough so the food does not stick, then the pot needs Libun Chamur.
  • Teflon/Enamel: If coated with enamel/Teflon then it may not be Kashered.

Water urn/Kumkum:

Water urns are to be Kashered for Pesach and it is thus advised to purchase a new one for Pesach. If the urn is made of metal, then it is to be Kashered through Hagalah.  If it contains plastic, it is disputed if it can be Kashered. In all cases, one must beware to remove the hardened calcium from the urn before Kashering.


  • A grater requires Libun Kal.

Appliances and furniture

The stove:

  • The grates: Need Libun Chamur. If one cannot do Libbun Chamor, then one is to clean it very well and wrap the grates in thick aluminum that will last throughout Pesach.
  • Burners: One is to clean the burners and use toothpicks or needles to remove any dirt or food from within the gas holes of the burner. Afterwards, turn on the fire for some time to accomplish Libun Kal.
  • Stove top surface: One is to clean the stove surface well and then do Iruiy Keli Rishon to it. If the surface is made of non-Kasherable material, such as enamel, that it must be covered with aluminum.
  • Knobs: One is to clean the stove knobs very well, cover them or attach clean replacement knobs.
  • Covering all items: Practically, the custom is that even after Kashering all the above items of the stove, one covers all the surfaces with aluminum.

Electric hot plate [Shabbos Plata]:

  • If possible, one is to purchase a new electric hot plate for Pesach.
  • In a time of need, one is to clean the entire hot plate, including the cord, its sides, and bottom areas, with a killing agent such as bleach. After 24 hours pass, one is to then turn the hot plate on to its hottest setting for some time and then pour boiling water over it.  One is to then cover the hot plate with a thick piece of tinfoil.  For extra care, one can place a second sheet of tinfoil or aluminum pan on the hot plate.


From the letter of the law an oven requires Libun Chamur. If one’s oven does not have a self-clean oven it is very difficult to accomplish Libun Chamur through using a blow torch, as the oven can break in the process. One is thus to buy a Pesach oven or alternatively Kasher it in the following way:

  1. Clean the oven well using a Chametz killing agent such as bleach or oven stain remover.
  2. Wait 24 hours prior to Kashering.
  3. Turn the oven on for a period of at least one hour to its highest temperature or blow torch the oven from the inside.
  4. After the Kashering process is complete one should cover the walls and floors with aluminum foil.

Self cleaning oven:

  1. An oven with self cleaning mode reaches a temperature of 900° F and is equivalent to Libun Chamur. An oven with a “Continuous cleaning” cycle is not equivalent to Libbun Chamur, and hence the above-mentioned method must be used.



  • If one is accustomed to place hot pots on his counter or table then the custom is to do Iruiy Keli Rishon with Even Meluban. However other surfaces on which one is not accustomed to place hot Chametz pots do not need to be Kashered.
  • Covering the counter or table: If one covers his table or counter then from the letter of the law it does not need to be Kashered. Likewise, if the counter or table has been Kashered it does not need to be covered. However, the custom is to do both, to Kasher and cover the areas.
  • The walls of the counter: They are to have Iruiy Keli Rishon performed and then covered.
  • Must one cover all kitchen surfaces such as tables, counters, cabinets, refrigerator shelves and the like?
  • From the letter of the law, once these areas have been properly cleaned and Kashered they may be used for all foods without any cover. However, some Poskim rule that one is to cover the surfaces even after they are Kashered due to suspicion that perhaps they still contain actual Chametz that was not properly removed. Practically, the widespread custom is to cover all items that contact food even after they have been cleaned and Kashered.



  • It is best to buy new tablecloths for Pesach. Nevertheless, from the letter of the law one may Kasher and use the tablecloths that he uses during the year. The following is how they are Kashered: One is to wash them with hot water and laundry detergent.


The Fridge:

  • One is to wash it down very well using a water based killing agent, such as bleach and the like.
  • The elastic insulation material: One must take special care to wash well the elastic area from Chametz crumbs. A suggestive form of cleaning is to use Q-tips dipped in bleach.
  • Bedikas Chametz: One is to perform Bedikas Chametz to his fridge prior to entering the Pesach foods back into or and prior to covering it shelves.
  • Covering the shelves: Some are accustomed to cover the shelves of the fridge. This is not required from the letter of the law.
  • Cord: One is to clean the electric cord of the fridge that enters into the outlet.


  • The actual sink: The Kashering of a sink is dependent on the material that it is made of. A metal sink can be Kashered through Iruiy Keli Rishon. Most sinks are made of Porcelain or enamel which are non-Kasherable materials and thus cannot be Kashered. Nevertheless, the custom is to do Iruiy Keli Rishon on such material sinks. One is then to insert a sink insert which will be used throughout Pesach.
  • The spout: The custom is to clean and wash the spouts of the sink as throughout the year they have been used with hands that are dirty from Chametz. [One is to pour boiling water of the spout, and leave it open with the hot water running.]
  • Knobs: Wash and clean.
  • The drain: Pour boiling water that contains bleach or Drano down the drain.
  • Metal strainer: Iruiy Keli Rishon.
  • Using the hot water on Pesach: It is advised not to use hot water that is over Yad Soledes [110° F] on Pesach, in a sink that is not Kasherable, as one can possibly Treif up the vessels in the sink through doing so. Thus, one should not turn on the hot water to the point of Yad Soledes and is likewise not to pour hot water into the sink. If the water is warm, below Yad Soledes, it may be poured into the sink. Likewise, if the hot water of a pot was placed in a Keli Sheiyni, it may be poured into the sink even if it is still very hot.


  • One is to purchase a new one for Pesach. If this is not possible, some Poskim rule the microwave is to be cleaned, not used for 24 hours and have water with bleach placed in it and heated for about 10-20 minutes, until it steams out.

Teeth; Fillings and Braces:

  • Natural teeth without fillings and the like: Do not have to be cleaned or Kashered from the letter of the law. Nevertheless, the custom is to clean them well and wash them with water to make sure that no crumb of Chametz has remained in one’s teeth.
  • Teeth with fillings: Although there is much room to say that they to need not to be Kashered, nevertheless practically the Rabbinical directive given is to clean them out prior to the 5th hour and then swish ones mouth with the hottest temperature of water, from a Keli Sheiyni, that he can intake. It is best to not eat hot Chametz 24 hours prior to doing so [Although this is a mere stringency and is not required.]
  • Braces: If possible, are to be removed by a dentist, cleaned and Kashered. If not possible, then one is to clean them to the best of his ability, and follow the above mentioned order for fillings.
  • Dentures: Are to be removed, cleaned and Kashered. If this is not possible then one is to clean them to the best of his ability, and follow the above mentioned order for fillings.

G. How does one do Hagalah?

  • Having an expert do the Hagalah: Since the laws of Hagalah involve many details, it should only be done by one who is expert in its laws.
  • When to Kasher: It is proper for a person to be careful to perform Hagalah to his vessels prior to the 5th hour on Erev Pesach. Some (meticulous) individuals are accustomed to perform Hagalah three days before Pesach.
  • Cleaning the vessels prior to Hagalah: One must remove any rust, dirt patches that are on the vessel prior to doing Hagalah to it, as the Hagalah must be done purely to the vessel. If one cannot remove the rust by hand then one may place a coal or flame on the rust spot until the other side becomes “Yad Soledes Bo” or until a piece of paper touching the outside gets scorched. Only the rust that is on the inside of the vessel needs to be removed, and only if it has substance to it. However, if it is just coloring or a stain, then it does not need to be removed at all as there is no suspicion that any food has been stuck under it. If the vessel has a crack in it which cannot be properly cleaned, then Hagalah does not help for such a vessel until one first does Libun to the crack. This however only applies if the crack is inside the vessel where it contacts food, however a crack the external part of the vessel does not need to have Libun performed on it. The company trademark that is on the vessel needs to be cleaned well. One should not Kasher a vessel which has paint on its interior, as it prevents the absorbed Chametz from leaving the walls of the pot.
  • Cleaning and drying the vessel before Hagalah: One needs to clean and dry the vessels before doing Hagalah.
  • Must the vessels stay 24 hours before Kashering: The custom is to only Kasher vessels which are not Ben Yomo, which means that they have remained without use for 24 hours.
  • The Hagala vessel: From the letter of the law, when Kashering prior to the 5th hour on Erev Pesach, one is not required to first Kasher the pot being used for Hagala even if it is Ben Yomo. Nevertheless, the custom is to Kasher the Hagala vessel prior to using it, if it was used for Chametz, even if it is not Ben Yomo. One is to spill out this water, and then reboil water in it for the Kashering. Due to the size of the Hagala pot, it often cannot be Kashered through entering it into a larger pot of boiling water. Rather, it is to be Kashered through boiling water inside of it until its very top and then throwing into the boiling water an Even Meluban [red hot stone or slab of metal] which will cause the water to overflow and splash beyond the rims of the pot. From the letter of the law, when Kashering prior to the 5th hour on Erev Pesach, one is not required to Kasher the Hagala pot a second time after the Kashering is finished, if it was already Kashered prior to the start of the Kashering [as explained above]. Nevertheless, the custom is to Kasher the Hagala vessel a second time after one finishes Kashering with it, if one plans to use it on Pesach. Thus, the vessel is Kashered twice; once before and once after the Kashering. This applies even if the Kashering was done before the 5th hour, and the vessels were not Ben Yomo, and one had 60x in the water. This applies even if the Hagala pot is only being used for Iruiy Keli Rishon.  It is not necessary to spill the Hagala water and reheat new water in the pot for the sake of the second Hagala, and rather one ay use this same water to use the Even Meluban to overflow it, as explained above.
  • Boiling water for Hagalah: The water used for Hagalah must be boiling. It does not suffice for it to just be Yad Soledes. Furthermore, the water must remain boiling when the vessel is dipped into it. If the water stopped boiling after one vessel, then one must wait for it to boil before placing in it another vessel.
  • How long does the vessel need to be placed into the water for? Some opinions say that one should place the vessel in for as much time as he accesses is needed to remove the foods that it has absorbed. However, the custom is to place it in and then immediately take it out. Nevertheless, one should leave the vessel in the water a little in order to allow the heat to penetrate the vessels thickness.
  • May one Kasher many vessels together in a sack/basket? One should not do so, as if the vessels touch each other then Hagalah does not help for those areas.
  • Washing the vessel after Hagalah: The custom is to wash the vessel in cold water immediately after Hagalah has been performed.

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