R' Meir said: From their words we infer that we may burn uncontaminated terumah [which is chametz] with contaminated terumah on Pesach.  R' Yose said to him: This is not analogous. [Even] R' Eliezer and R' Yehoshua concur that each is burned separately. Concerning what do they differ? — Concerning suspended and contaminated [terumah], where R' Eliezer says that each must be burned separately, but R' Yehoshua says that both [may be burned] together.

As long as it is permitted to eat [chametz], one may feed [it] to livestock, beasts, and birds, and sell it to a Gentile, and [deriving] benefit from it is permitted. When its period has passed, [deriving] benefit from it is forbidden, and one may not fire an oven or a range with it.  R' Yehudah says: There is no removal of chametz except by burning. But the Sages say: He may also crumble [it] and throw [it] to the wind or cast [it] into the sea.