Shulchan Arukh Orach Chayim · Siman 445

English

The laws of destroying hametz... How is hametz destroyed? He burns it or crumbles it up and throws it into the wind or casts it into the sea. And if the hametz was hard and the sea would not cause it to break up quickly, he must first crumble it up and then throw it into the sea. Hagah: And the custom is to burn it in the day similar to the leftovers of sacrifices that were burned in the day (da'at atzmo). But if he wants to burn it immediately after the searching in order that a rodent will not drag it, the option is his (Hagahot Maimoniyyot, Kol Bo)

English

If one gave it to a non-Jew before the sixth hour, he is not required to destroy it. If he burned it before the sixth hour, it is permitted to benefit from its coals during Pesach. However, if he burned it from the sixth hour and onward, since it is forbidden to derive benefit from it, he may not use it to fuel an oven or a stove, nor to cook. If he did cook or bake, that bread and that dish are forbidden to benefit from, and likewise its coals are forbidden to benefit from, since he burned it after it became prohibited for benefit.

English

Before the time of its prohibition, he may throw it in a place where ravens are found; if he finds it after the time of prohibition and the ravens have not eaten it, even though the place is ownerless, he may not leave it there but must destroy it. (And if he did not find any chametz when he checked, he should burn the utensil he used for the inspection so that he does not forget the obligation of destruction.) (Maharil).