One of the many preparations one must make for Pesach is kashering, a process to prepare chametz vessels for Pesach use. Although most people only kasher their utensils in preparation for Pesach, the following directions apply to kashering utensils all year-round as well.
As with all areas of halachah, those who are unsure of how to apply the rules of kashering to their situation should consult their local Orthodox Rabbi.
There are two steps in kashering:
1) Cleaning—removing all tangible traces of chametz
2) Purging—using heat to remove all absorbed chametz flavor
All chametz utensils that will be used for Pesach must first be thoroughly cleaned. This involves the removal of all food, rust, dirt, calcium deposits and anything else that protrudes (excluding the removal of discolorations).
Items which have narrow cracks, crevices, deep scratches or other areas that cannot easily be cleaned, cannot be kashered for Pesach.
Examples of items that cannot be kashered:
Additionally, the common custom is to cover tables, counters, refrigerator shelves and other areas where one might not have been able to clean away every trace of chametz.
In addition to cleaning, most items require some form of hot purging in order to remove the flavor that has been absorbed. As a rule, any utensil that came in contact with hot food, was washed with hot water or was used to store liquids, requires hot purging.
A comprehensive analysis regarding when hot purging is required and how one determines which form of purging is effective is beyond the scope of this article. Rather we will describe the standard method of purging flavor from the most common items.
You should consult your local Rabbi. If a synthetic material is a minority component of a substance (like Silestone), many rabbis believe that one may kasher it, even if one does not normally kasher artificial materials for a number of reasons.
As a rule, materials such as fabric, metal, wood, rubber and stone (for example, granite and marble) can be kashered.
Note: All methods of kashering noted in this section presuppose that the equipment was thoroughly cleaned, as described above.
Small items are kashered with hagalah, which involves:
If the oven has a separate broiler chamber, it should be kashered in the same manner as the oven chamber. A broiler pan that comes in direct contact with food cannot be kashered.
Note: The method of kashering described above is based on the ruling of Rav Aharon Kotler zt’l. However, Rav Moshe ruled that the oven must either be kashered with a blowtorch, or that an insert should be placed into the oven for the duration of Pesach. Consult your own Rabbi for guidance.
The grates of a gas stovetop should be kashered in the oven chamber in the same manner described above. For an electric stovetop, just clean the coils and turn on high for ten minutes. If you have a glass-topped stovetop, you should consult your Rabbi for directions on if/how it can be used for Pesach.
For a gas or electric stove, it is preferable to replace the drip pans that are under the burners; if this isn’t possible, the area should be covered with aluminum foil. The work area between the burners should be cleaned and covered with aluminum foil. The knobs and handles of the oven and stovetop should be wiped clean.
Since a porcelain sink cannot be kashered, one should kasher the faucet and knobs as outlined above and, for the duration of Pesach, place a basin (or insert) into the sink. All dishes, silverware, etc., should be washed in the basin, and wash-water can be disposed of through the sink’s drain. One should be careful not to allow the sink to fill with hot water while the basin is in the sink.
Wait twenty four hours since using the microwave and make sure that the microwave is clean. One should then heat water in the microwave for twenty minutes and then also pour boiling water over the bottom of the microwave oven. If one cannot pour boiling water over the bottom of the microwave oven, then after heating water for twenty minutes one should move the container to another spot and repeat the heating procedure again. The glass plate should be either covered or replaced for Passover.
To kasher a dishwasher, one should wait twenty four hours, make sure that the dishwasher is clean, and then run two cycles. If the dishwasher is plastic, there is a debate as to whether one may kasher it, and an Orthodox rabbi should be consulted. Ceramic dishwashers cannot be used for an entire year before they are kashered them. Therefore, we cannot recommend a way of kashering a ceramic dishwasher for Passover.
These areas should be thoroughly cleaned—paying special attention to the edges where crumbs may get trapped—and the shelves lined with paper or plastic. The refrigerator and freezer will operate more efficiently if one pokes a few holes in the lining.
Any item made of fabric can be kashered by washing it in a washing machine set on ‘hot’ and then checking to make sure that no pieces of food remain attached to it. Vinyl and plastic-lined tablecloths cannot be kashered.