Numbers 19:17-18

17“To remove the defilement, put some of the ashes from the burnt purification offering in a jar, and pour fresh water over them.

18Then someone who is ceremonially clean must take a hyssop branch and dip it into the water. That person must sprinkle the water on the tent, on all the furnishings in the tent, and on the people who were in the tent; also on the person who touched a human bone, or touched someone who was killed or who died naturally, or touched a grave.