Pesachim 1:7-2:1
Pesachim 1:7
Rabbi Meir said that we can infer from the previous mishna that ritually-pure and ritually-impure terumah were burned together on Passover. Rabbi Yosi disagreed with Rabbi Meir’s conclusions, saying that the situations were different. (The previous mishna dealt with things that were of different degrees of impurity, while in this case the terumah is ritually pure.) Rabbi Eliezer and Rabbi Yehoshua agree in this case that the clean and unclean terumah are burned separately. They disagreed in the case of “suspended” terumah (whose state of purity or impurity is unclear) and definitely-unclean terumah. Rabbi Eliezer says that they had to be burned separately but Rabbi Yehoshua says that they were burned together.
Pesachim 2:1
As long as it is permitted to eat chometz, it may also be fed to animals and birds, sold to non-Jews, and used for other forms of benefit. Once one may no longer eat chometz, one may no longer derive benefit from it. Even though the chometz must be destroyed, one may not use it as fuel in an oven (as this would be a form of benefit). Rabbi Yehuda says that chometz must only be destroyed by burning but the Sages say that it may be scattered and thrown to the wind or tossed into the sea.