Question: I found a bottle of whisky among my wine on chol hamoed Pesach. What should I do?
Answer: The Shulchan Aruch (OC 446:1) writes that one who finds chametz in their home on chol hamoed must remove it from their house and burn it immediately (See Mishna Berura 445:6). The Taz (OC 446:1) explains that it isn’t good enough to just remove it from one’s house as one can still own something that isn’t in their property. It is important that it is removed immediately to prevent anyone from eating it (See Mishna Berura 446:1).
Providing that one annulled their chametz by saying kol chamira on erev Pesach, there is no issur mideoraisa of owning chametz. Nonetheless, the Magen Avraham (OC 446:1) and Baer Heitev (OC 446:2) write that one should still say the beracha, ‘al biur chametz’ when burning it as this chametz wouldn’t have been included and miderabanan there is still an issur in owning such chametz. The Kitzur Shulchan Aruch (111:17) writes that this would only apply if there was a kezayis worth of proper chametz.
The Mishna Berura (435:5), however, disagrees, writing that there is a machlokes as to whether one needs to say a beracha if one already annulled the chametz before Pesach. As safek berachos lehakel¸ one shouldn’t recite a beracha upon burning it.
R’ Shmuel Wosner (Shevet Halevi 6:53; 9:116) writes that when one has sold their chametz to a non-Jewish person, the issue becomes more complex. If it belongs to the non-Jewish person then were one to destroy it, they’d be stealing from them. On the other hand, any chametz that one sold should have been locked away separately. Ideally, one should ask a non-Jewish person to move this item into the cupboard or room with the chametz. Failing that, they should declare that they don’t want to acquire the chametz before putting it away (See Teshuvos Vehanhagos 2:229; Rivevos Ephraim 4:113:66).In conclusion, providing one has sold their chametz before Pesach, this chametz belongs to the non-Jewish person. It should therefore be moved quickly and placed with the rest of one’s sold chametz.