Numbers 19:8-9

19:8 The one who burns it must wash his clothes in water and bathe himself in water. He will be ceremonially unclean until evening.

19:9 “‘Then a man who is ceremonially clean must gather up the ashes of the red heifer and put them in a ceremonially clean place outside the camp. They must be kept for the community of the Israelites for use in the water of purification – it is a purification for sin.

Numbers 19:12-13

19:12 He must purify himself with water on the third day and on the seventh day, and so will be clean. But if he does not purify himself on the third day and the seventh day, then he will not be clean. 19:13 Anyone who touches the corpse of any dead person and does not purify himself defiles the tabernacle of the Lord. And that person must be cut off from Israel, because the water of purification was not sprinkled on him. He will be unclean; his uncleanness remains on him.