A common method for relinquishing ownership of chametz is to sell it, typically through an agent (a rabbi), to a gentile. The chametzremains in the house, in a closed-off area (e.g. a closet) that has been rented to its new owner. After Pesach the rental period ends, and the agent purchases the chametz back on behalf of the original owner.
This option is time-honored and halachically acceptable. Some, however, do not want to rely on such a sale for chametz that, on a Torah level, a person is required to remove from their possession.
The Torah prohibition against owning chametz applies not only to obvious chametz such as bread, pretzels, or cookies, but to any product that contains a chametz ingredient that constitutes a k’zayit within that product. Licorice, for example, which contains a significant amount of flour in its dough, would not be sold according to this position but should, instead, be eaten before Pesach, burned, or otherwise destroyed. Such products are considered chametz gamur — “real” chametz.
If the food is only safek chametz (that is, there is some doubt as to whether it is chametz at all), it may be included in the sale even according to those individuals who avoid the sale of chametz gamur.
The foods listed in the chart are identified either as chametz gamur and, according to the stringent position, should not be included in a sale, or “not chametz gamur,” and may be included in a sale.
Many people who avoid selling chametz gamur nonetheless have a family custom to sell their whiskey.