Numbers 19:7 KJV

5And one shall burn the heifer in his sight; her skin, and her flesh, and her blood, with her dung, shall he burn:

6And the priest shall take cedar wood, and hyssop, and scarlet, and cast it into the midst of the burning of the heifer.

7Then the priest shall wash his clothes, and he shall bathe his flesh in water, and afterward he shall come into the camp, and the priest shall be unclean until the even.

8And he that burneth her shall wash his clothes in water, and bathe his flesh in water, and shall be unclean until the even.

9And a man that is clean shall gather up the ashes of the heifer, and lay them up without the camp in a clean place, and it shall be kept for the congregation of the children of Israel for a water of separation: it is a purification for sin.