Numbers 19:17-18

17“⌞This is what you must do⌟ for people who become unclean from touching a dead body. Put some of the ashes from the red cow that was burned as an offering for sin into a container. Then pour fresh water on them.

18A person who is clean will take a sprig of hyssop, dip it in the water, and sprinkle the tent, all the furnishings, and all the people who were in the tent ⌞with the dead body⌟. He must also sprinkle any person who has touched a human bone or a grave and any person who has touched someone who has been killed or who has died naturally.