1,108. Leaving Home, Leaving Chometz Behind

Chometz u’Matzah 3:8

If a person does not nullify his chometz before the sixth hour and then he finds some that he considered important and forgot about at the time when chometz is destroyed, he has not destroyed it, thereby violating the prohibition against seeing and finding chometz. He has not destroyed this chometz, nor nullified it, and nullifying it at this time would be ineffective as the chometz is no longer in his possession. Nevertheless, the Torah considers it in his possession as far as the prohibition against seeing and finding chometz, with the result that one must destroy whatever chometz one may find. If one finds chometz on yom tov, it should be covered with a vessel until after yom tov, then destroyed. If the chometz was consecrated, it need not be covered because everyone would avoid using it anyway.

Chometz u’Matzah 3:9

What if someone left his house before the time to destroy chometz in order to perform a mitzvah or to participate in the meal of a mitzvah, like a wedding, and he then remembers that he still has chometz at home? If it is possible to return home and destroy the chometz and then return to the mitzvah, he should go back. If not, he should just nullify the chometz in his heart. If one has gone to save someone from enemy forces, a flood, a fire or from being buried under debris, all he need do is to nullify the chometz in his heart. If one has gone out for his own purposes and he remembers that he has chometz at home, he must go back immediately. The amount of chometz necessary to require one to turn back is the volume of an egg. If it is any smaller than this, it is sufficient for one to nullify the chometz in his heart.