Numbers 19:7-10
7 Then the priest must wash his clothes and bathe his body in water; after that he may enter the camp, but he will remain ceremonially unclean until evening.
8 The one who burned the cow must also wash his clothes and bathe his body in water, and he will remain unclean until evening.
9 “A man who is clean is to gather up the cow’s ashes and deposit them outside the camp in a ceremonially clean place. The ashes must be kept by the Israelite community for preparing the water to remove impurity; it is a sin offering.(A)
10 Then the one who gathers up the cow’s ashes must wash his clothes, and he will remain unclean until evening. This is a permanent statute for the Israelites and for the foreigner who resides among them.