I wanted to mention a short but important halacha related to burning the chametz.
There are two views in the Mishnah (Pesachim 21a) concerning the proper procedure for fulfilling the mitzvah of tashbisu, the Torah’s command to destroy all chometz on erev Pesach. The basic halachah is that tashbisu is accomplished by getting rid of chometz in any of the following ways: Burning it; crumbling it and throwing it to the winds; crumbling it and throwing it into an ocean or river etc. L’chatchilah, though, it has become customary to follow the view of R’ Yehudah who holds that burning in fire is the only legitimate method of getting rid of chometz (biur chometz) (Rama 445:1).
Harav Shlomo Zalman Auerbach zt”l (Halichos Shlomo page 138) mentions that it is not advisable to pour lighter fluid, gasoline or other combustible materials over the chometz before burning it, for then the chometz becomes inedible – “destroyed” – by the gasoline, etc., rather than by the fire, and as mentioned before, this should be avoided. One should therefore be careful to leave at least a cezayis of chametz (the minimum amount required to burn) untouched by lighter fluid or other chemicals. Once a cezayis of chametz is sufficiently burned one may pour lighter fluid on the remaining bread to speed up the burning process.