If someone founds chametz in their house during Pesach the Shulchan Aruch writes that if it's Chol HaMoed one must go out and burn it immediately and if it's Yom Tov ne should put a cli over it and then after Yom Tov burn it (See Shulchan Aruch Orach Chaim Siman 446 Sif 1.) However how does this din apply nowadays in a case where a person "sold" their chametz to a goy before Pesach. While generally they sell all the chametz that is in a particular location, however many also write "b'col makom shehu" (in any place that chametz is found.) If a person would find a cookie or piece cake or a slice of bread in a random place in their house, what should be done with it? Does it "belong" to the goy and therefore should be set aside for them? Or should it be burned like it says in Shulchan Aruch?
(I have hard time imagining the goy caring about a dry piece of bread, but if the sell is supposed to be real then maybe it really does belong to him.)