584. What Do I Do If I Find Chametz on Pesach?
According to the original law (without the consideration described below), chametz that is discovered on erev Pesach anytime between the deadline for removing or destroying chametz and sunset (shekiah) must be destroyed completely as soon as it is discovered.
The same is true of chametz discovered during chol ha-mo’ed. If it is discovered during yom tov or Shabbos chol ha-mo’ed, it must be securely covered so that it cannot be seen, and then destroyed completely immediately after Shabbos or yom tov.
When destroying chametz during Pesach, one recites the blessing … al bi’ur chametz – provided that there is at least the quantity of a kezayis and that it is considered true chametz.
Nowadays, however, it is customary to include the phrase, be-chol makom she-hu, “wherever it may be,” in the contract by which the chametz is sold to a non-Jew. Therefore, some authorities consider any chametz discovered during Pesach as belonging to the non-Jew, and it should be placed along with the other items that have been sold to the non-Jew.
One who wishes to be stringent and to burn the chametz, out of concern that it may not be included in the sale, should not recite a blessing over its destruction. Destroying the chametz is not considered theft from a non-Jew because he intends to pay the non-Jew for the destroyed chametz, should he demand it, and one is technically permitted to take an item in advance from a non-Jew with the intention of paying for it subsequently. When doing so, one must have in mind that he does not intend to acquire the chametz. For this reason, it is best to avoid touching it directly; he should move it with a stick or some similar method.