The night before Passover, about an hour after sunset, we must search the house for any bread or leaven products.

The Torah forbids us to have in our possession any bread, leaven, leavening agent, or any food that contains any of those, from the day before Passover until the end of the eighth day of Passover. We call any such item «chometz.« Before Passover, we must clean our homes thoroughly, and remove any chometz. Not even the smallest particle of chometz may be in our homes, even if we don’t know it exists. We must therefore search our homes to the light of a candle the night before Passover. The light of a candle in the darkness can reach into small, tight areas, including cracks and behind the furniture.

If the night before Passover is a Friday night, this procedure must be done on Thursday night.

Take a few pieces of bread and wrap them carefully in plastic sandwich bags (or something else equally safe) so that no crumbs can fall out, and place them where you can easily find them. This is so that if you find no chometz in your home, you will have still fulfilled the Commandment to remove chometz from your home the day before Passover.

Light the candle. Turn off the lights. Recite the following blessing:

Blessed are You Hashem, our G-d, King of the universe, Who has made us holy with His commandments and commanded us
concerning the destruction of chometz.

Search every part of the house into which chometz has ever been brought, including behind the furniture and cracks in the walls if it is possible that chometz may have been placed or may have fallen there. If children have been in the house, you must take into account areas into which a child is likely to bring food.

After the search, place all the pieces of chometz into a bag. The owner of the chometz and the person who lives in that property recite the following:

I hereby relinquish any association or ownership to all and any leaven or leavening agents in my possession that I did not see, or did not find, and that I have not destroyed, or that I do not know
about. They are null and ownerless, just like dust on the ground.

Put the bag of chometz away until tomorrow morning. The following morning, as early as possible, take the chometz outside and burn it. When it is all burned, and there is nothing left but ash, recite:

I hereby relinquish any association or ownership to all and any leaven or leavening agents in my possession, whether or not I saw them, whether or not I found them, and whether or not I destroyed them. They are null and ownerless, just like dust on the ground.