Leviticus 16:27, 30

And the bullock for the sin offering, and the goat for the sin offering, whose blood was brought in to make atonement in the holy place, shall one carry forth without the camp; and they shall burn in the fire their skins, and their flesh, and their dung.

for on that day shall the priest make an atonement for you, to cleanse you, that ye may be clean from all your sins before the LORD.