Thus, a person who does not nullify [his chametz] before the sixth hour and discovers chametz which he:
considered important and [valued] in his heart,
then forgot at the time of the destruction of chametz,
and hence did not destroy,
transgresses [the prohibitions]: "[leaven] shall not be seen" and "[leaven] shall not be found."
Behold, he has neither destroyed nor nullified [his chametz], and nullification at this time would not be effective, for [the chametz] is no longer in his possession. Even so, the Torah considers it as if it were in his possession, to obligate him for [transgression of the commandments:] "[leaven] shall not be seen" and "[leaven] shall not be found."
[Therefore,] he is obligated to destroy it whenever he finds it. If he finds it on the day of a festival, he should cover it with a utensil until the evening, and then destroy it. [If the chametz] was consecrated property, there is no need to cover it with a utensil, for regardless, everyone shies away from its use.