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Kashering Your Kitchen - From the JLIC Orthodox Rabbi:
by R. Yehudah Seif & R. Mordy Friedman

Ovens
In a conventional oven, gas or electric, the oven must be completely clean before kashering can begin. Oven cleaner may be necessary to remove baked on grease. If a caustic type of oven cleaner (such as Easy-Off) was used to clean the oven and some stubborn spots remain after the caustic cleaner has been applied a second time with similar results, the remaining spots may be disregarded. Once the oven and racks have been cleaned, they may be kashered by Libbun Kal. Turning the oven to the broil setting for 2 hours satisfies the requirement of Libbun Kal. In a gas oven the broil setting will allow the flame to burn continuously. In a conventional electric oven the highest setting, broil or 550 oF, kashers the oven after two hours.

In a continuous cleaning oven, one cannot assume that such an oven is clean because the manufacturer claims it to be continuously clean. A visual inspection is required. Since caustic or abrasive oven cleaners, e.g. Easy-Off, cannot be used without destroying the continuous clean properties of the oven, a non-abrasive, and non-caustic, cleaner must be used to clean the oven. Grease spots will usually disappear if the top layer of grease is cleaned with Fantastic and a nylon brush. Then the oven should be turned on to 450 oF for 2 hours so that the continuous clean mechanism can work. If the spots don't disappear the oven should be left on for a few hours to allow the continuous clean mechanism to deep clean. If the spots do not disappear, the spots should be removed with oven cleaner or steel wool. If the spots are dark spots that crumble, they can be disregarded. In all of the above cases the oven should then be kashered by turning the oven to the broil setting for 2 hours.

In a self-cleaning oven, the self-cleaning cycle will clean and kasher the oven simultaneously. This is true for convection ovens with a self-cleaning feature as well. The oven need not be cleaned well before the process begins because everything inside of the oven is reduced to ash. The oven door and rubber around the door should, however, be completely clean before beginning the self-clean cycle.

Oven Racks are very difficult to thoroughly clean. It is therefore recommended that they either be placed into a self-cleaning oven or covered with foil (punching holes though to allow the air to circulate.)

Oven Broiler: The broiler pan and grill cannot be kashered by just turning on the gas or electricity. Since food is cooked directly on the pan or grill, they must be heated to a glow. An alternate method is to replace the pan with a new pan and Kasher the empty broiler cavity by cleaning and setting it to broil for 2 hours.

Cooktop: On a gas range the cast iron or metal grates upon which the pots on the range sit may be inserted into the oven after they have been thoroughly cleaned. (If one has a self-cleaning oven one need not clean the grates first.) The grates can be kashered simultaneously with the oven. Another method of kashering the burners is to place a blech (all year round belch may be used) or heavy foil over each burner and turn on highest temperature for 15 minutes. (For safety concerns it is recommended to do one burner at a time.) The rest of the range should be cleaned and covered with a double layer of heavy-duty aluminum foil. (Stainless steel stove tops may be purged with boiling water and need not be covered.) The burners themselves do not need Kashering or covering but should be thoroughly cleaned. The drip pans should be thoroughly cleaned and need not be kashered. Kashering a Glass, Corning, Halogen or Ceranelectric range top is a very difficult task. The elements of the stove can be turned on until they come to a glow. The burner areas are now considered Kosher. However, the rest of the cook top presents a serious Kashering problem. The unheated area of glass top ranges cannot be covered with foil like conventional or porcelain tops. Since glass tops are made of tempered glass, and are not meant to be covered, there is a risk that the glass cooktop will shatter if it is covered. Therefore, one should check with the company before attempting to kasher a Corningstove top. In an electric cooktop, one only needs to turn the burners on the high heat setting for 5 minutes in order to kasher them, since the burners come to a glow in a few minutes. The remaining cooktop areas should be covered. The knobs with which the gas or electricity is turned on should be cleaned. No other process is necessary to kasher the knobs.

Microwave Ovens
Clean the microwave thoroughly and do not use for 24 hours. Then boil a cup of water on the highest setting for 20 minutes, or until all the water has boiled off. The glass plate (if you have one) should be replaced, or the plate should be covered, or one should make sure that no food comes in direct contact with the glass plate, meaning food should never be heated directly on the glass plate. If your microwave walls have holes or grates through which food has fallen and cannot be removed, it’s best to cover all foods that you heat in the microwave.

Metal Utensils
Metal Utensils that have been used for cooking, serving or eating questionable food can be koshered by cleaning them thoroughly, waiting twenty-four (24) hours and then immersing them (known as hagala), one by one, into a very large Kosher pot of water (60 times the volume of whatever you are putting in) which has been heated and is maintaining a rolling boil when the vessel is immersed. In addition, some soap should be added to the . Note that Teflon coated pots can not be kashered.

The utensils undergoing the kashering process may not touch each other on the way in to the pot. In other words, if a set of flatware is being kashered, one cannot take all the knives, forks and spoons and put them in the boiling water together. They should be placed into the boiling water one by one. The process is finalized by rinsing the kashered items in cold water. If tongs are used to grip the utensil, they should be loosened for a moment while the utensil is underwater. Otherwise, the utensil will have to be immersed a second time with the tong in a different position so that the boiling water will touch the initially gripped area. The entire utensil does not have to be kashered at once; it may be done in parts. Please watch out for utensils that are rusty or difficult to clean properly. Even silverware made of two parts (a handle and a blade, for instance) should most often not be kashered.

Sinks
Stainless steel sinks can be kashered by the following method. Clean the sink thoroughly. Hot water should not be used or poured in the sink for twenty-four (24) hours prior to kashering. (It is recommended that the sink be covered or the hot water knob covered or removed, etc. to insure that it is not used.) Kashering is accomplished by pouring boiling hot water kettle/pot over every part of the stainless steel sink. The poured water must touch every part of the sink including the drain and the spout of the water faucet. It is likely that the kashering kettle(s) will need to be refilled a few times before the kashering can be completed. Granite sinks can be kashered like a stainless steel sink.

China sinks cannot be kashered at all. Porcelain or corian sinks should also be considered like a china sink, since there is a controversy whether these materials can be kashered. Therefore, do not place hot dishes directly into the sink, and always have a rack (insert) on the bottom of your sink (one for meat and a separate one for dairy) so that the dishes do not touch the bottom of the sink.

Countertops
Countertops made of granite may also be kashered. Formica countertops should be cleaned and covered with a waterproof material. The same goes for tables with synthetic tops. Wood tables could theoretically be kashered with boiling water, but the custom is to clean and cover them.

Dishwashers
Porcelain and enamel dishwashers cannot be kashered. Stainless steel dishwashers may be kashered but the racks should be replaced. These dishwashers must be thoroughly cleaned. Please contact a rabbi before doing so.