NOTE: Items with pinch welds, rolled edges, hinges, rivets and other small crevices, can be impossible or nearly impossible to clean. These areas must be kashered with libun kal until the food residue/ grease is released. Items made from wood, plastic, or other flammable material, cannot be kashered. This applies to all equipment and small wares that require kashering.
General Principles
The basic premise behind Kashering is known as “K’bol’o, kach polto” — the very manner in which the item became non-permissible is the manner in which we Kasher to make it permissible.
STOVES
Gas Range — Clean thoroughly. Cover burners with a blech (sheet metal) and turn on high for 20 minutes. If you have concerns about the electric control panel, Kasher each burner one at a time. The area between the burners usually cannot be Kashered. After Kashering, remove burner grates and cover the stove top with aluminum foil and replace grates. Be sure not to obstruct any gas or air vents.
Electric Coil — Clean thoroughly. Turn coils on high for 15 minutes. If you have grates, place them on top of the coils. Cover burners with a blech (sheet metal) and turn on high for 30 minutes. The area between the burners usually cannot be Kashered. After Kashering, remove burner grates and cover the stove top with aluminum foil and replace grates. Be sure not to obstruct any air vents.
Electric Glass Top — (It is questionable if this type of stove can be Kashered. Please consult with your Rabbi prior to Kashering.) Clean thoroughly. The burners MUST be Kashered one at a time or the glass will crack. Cover each burner with aluminum foil and turn on high for 30 minutes. Even according to those who allow Kashering glass top stoves, the area between the burners is not Kasherable but also cannot be safely covered with aluminum foil.
Electric Induction Cooktop — Clean thoroughly and don’t use it for 24 hours. Boil a completely full pot (unused for 24 hours) on the induction cooktop. As the water boils, allow it to boil over onto the cooktop. Move the pot around while it boils over, allowing it to spill over the entire cooktop. After Kashering, use with a Pesach induction diffuser plate.
OVENS
Self-Cleaning Ovens — The self-cleaning cycle qualifies as a Libun Chamur. You don’t need to clean the oven or wait 24 hours prior to Kashering. (Many cover the glass door of the oven with aluminum foil for the duration of Pesach. If you do not want to cover the door, the oven should not be used for 24 hours prior to Kashering. Please consult your Rabbi)
NOTE: Continuous clean, steam clean, and aqua clean do not qualify for any type of Kashering. Such ovens should be treated as non self-clean ovens.
Non Self-Cleaning Ovens — All surfaces of the ovens, racks, and door must be completely clean and unused for 24 hours. Heat oven to 550°F (or 500°F if that is the highest temperature) for 2 hours. (Some cover the racks with foil, perforating for air circulation for the duration of Pesach. Please consult your Rabbi.)
Microwaves — (Many authorities do not allow microwaves to be Kashered. Please consult with your Rabbi prior to Kashering.) Clean thoroughly and do not use it for 24 hours. Place a large microwavable container filled with water in the microwave and run on high power until the steam fills the microwave with condensation. This can take 10 minutes or longer. Then move the container, and run the cycle again to Kasher the area where the container originally was. The glass turntable should not be used.
Heating / Warmer Drawers — Thoroughly clean and do not use for 24 hours. Place one gel sterno can and let it burn for 2 hours. Be sure to leave the drawer a crack open so the flame is not suffocated.
COUNTERS & SINKS
Counters — The procedure for Kashering countertops is the same regardless of the material. Clean thoroughly and do not use hot water on the counter surface for 24 hours. Pour boiling water over every spot of the counter, ensuring that every spot is hit with a direct stream of boiling water. This is best accomplished using a kettle so you can easily control the flow of water.
Sinks — Clean thoroughly and do not use hot water for 24 hours. Pour boiling water over every spot of the sink, ensuring that every spot is hit with a direct stream of boiling water. Start on the bottom, middle, center working your way outwards and across the sink in straight lines. For the walls, start on the bottom and work your way up in straight lines.
NOTE: Porcelain sinks or counters cannot be Kashered. Clean thoroughly and cover with contact paper or use a sink insert.
FLATWARE & POTS
Flatware — Clean thoroughly and do not use for 24 hours. Pay special attention to serrated knives and fork tines. Boil a pot or disposable pan of water. While the water is boiling, gently drop flatware in, one piece at a time. Remove from water and rinse in cold water.
Pots — Clean thoroughly, paying special attention to the seams, handles, and rivets. Fill the pot and boil.
PRO TIP: An inexpensive wire brush works wonders for cleaning seams, handles, and rivets before Kashering.
When the water reaches a boil, using a tongs, place a rock in the fire under the pot. When the rock is heated, place the rock in the pot and the water will boil over, Kashering the rest of the pot.
PRO TIP: If you do not wish to bother with the “heated rock” method for large pots, you can empty the pot after boiling. Fill a disposable roaster pan with water and place it on the fire to boil. While holding the pot on its side, dip it gently into the pan and slowly roll it until all sides have been hit by the boiling water.
PANS
Baking and Roasting Pans — Baking and roasting pans require Libun Chamur (intense heat), which is likely to damage them; therefore, they should not be Kashered.
Enamel Coated Pans — These cannot be Kashered.
Frying Pans — When used with liquid, a frying pan can be Kashered like a pot (from Chametz to Pesach only). Frying pans cannot be Kashered from non-Kosher to Kosher. Teflon-coated and searing pans are usually used dry or with minimal oil, requiring Libun Chamur which is likely to damage them; therefore, they should not be Kashered.
SMALL APPLIANCES
Toasters & Grills — Toasters, sandwich makers, panini presses, and electric grills cannot be Kashered.
Mixers & Blenders — Ideally, purchase separate ones for Pesach. If the motor base is completely sealed and can be cleaned thoroughly, it can be used. However, mixing bowls and accessories (including blender jars and immersion blades) should be purchased new.