Since it is prohibited to possess chametz on Passover, any chametz left un-disposed must be sold to a non-Jew.
All such chametz, as well as all chametz utensils that were not thoroughly cleaned, should be stored away. The storage area should be locked or taped shut for the duration of the holiday.
Since there are many legal intricacies involved in this sale, a rabbi acts as our agent both to sell the chametz to the non-Jew on the morning before Passover and also to buy it back the evening after Passover ends.
MECHIRAS CHOMETZ – DELEGATION OF POWER FOR SALE OF CHOMETZ -5778/2017
Please read the entire bill of sale:
I, the undersigned, fully empower and permit Rabbi Mordechai Gutnick to act in my place and stead and on my behalf to sell all Chometz possessed by me, knowingly or unknowingly, as defined by the Torah and Rabbinic law (e.g. Chometz, possible Chometz and all kinds of Chometz mixtures). Also Chometz that tends to harden and adhere to inside surfaces of pans, pots or cooking and usable utensils, and all kinds of live animals and pets that have been eating Chometz or mixtures thereof. He is also empowered to lease all places wherein or whereon the Chometz owned by me may be found, particularly in the premises listed below and elsewhere. Rabbi Mordechai Gutnick has full right to appoint any agent or substitute in his stead and said substitute shall have full right to sell and lease as provided herein. This power is in conformity with all Torah, Rabbinic and Civil laws.