R' Chanina, administrator of the Kohanim, says: In all the days of the Kohanim, never did they refrain from burning [sacrificial] meat that had been contaminated by a secondary tumah together with [sacrificial] meat that had been contaminated by a primary tumah, although [by so doing] they added contamination to its contamination.  R' Akiva added, saying: In all the days of the Kohanim, never did they refrain from lighting oil that had become unfit [through contact] with a t'vul yom in a lamp that had been contaminated by one contaminated by a corpse, although [by so doing] they added contamination to its contamination.

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.

Chametz of a Gentile over which Pesach has passed, [deriving] benefit from it is permitted; but [chametz] of a Jew, [deriving] benefit from it is forbidden —- since it is said: Nor shall leaven be seen with you (Exodus 13:7).