The remains of the bull used for the sin offering and the goat for the sin offering, whose blood was brought into the Most Holy Place to purify it, must be taken outside the camp. Their skin, meat, and waste must be burned.
all the rest of it—he has to take outside the camp to a place that is ceremonially clean, where the ashes are dumped, and he must burn it on a wood fire there on the ash heap.
Then he shall take the bull outside the camp and burn it, just as he burned the bull previously mentioned. It is the sin offering for the whole community.
Then a man who is clean shall collect the ashes of the cow and keep them in a clean place outside the camp. They are to be kept by the Israelites to prepare the water of purification which is for purifying from sin.
Nadab and Abihu died in the Lord's presence when they offered forbidden fire before the Lord in the Sinai desert. Since they didn't have any sons, Eleazar and Ithamar served as priests while their father Aaron was alive.