Leviticus 4:12; Leviticus 4:21

12 that is, all the rest of the bull, he is to bring out to a clean place outside the camp where the ashes are poured out, and burn it on wood with fire; where the ashes are poured out it shall be burned.

21 'Then he is to bring out the bull to a place outside the camp and burn it as he burned the first bull; it is the sin offering for the assembly.