Meat from kodshei kodshim [olah etc.], that became tamai in any way is burned in the bais hamikdash. Bais Shammai says if it became tamai from an av hatumah outside the Bais Hamikdash then we leave it outside to be burnt. Bais Hillel says all are burnt outside the Bais Hamikdash except if it became tamai inside the Bais Hamikdash by a secondary tumah [rishone or sheni].

Shikalim 8:7

[This is a continuation of the previous mishna.]

R’ Akiva says wherever it became tamai, that is where you burn it.

R’ Eliezer says the meat that became tamai with an av hatumah, you always burn outside the Bais Hamikdash. If it became tamai with a secondary tumah then it is burned in the Bais Hamikdash.