Numbers 31:19-24 - Purification After Battle
19 "Encamp outside of the camp seven days: whoever has killed any person, and whoever has touched any slain, purify yourselves on the third day and on the seventh day, you and your captives. 20 As to every garment, and all that is made of skin, and all work of goats' [hair], and all things made of wood, you shall purify yourselves."
21 Eleazar the priest said to the men of war who went to the battle, "This is the statute of the law which Yahweh has commanded Moses: 22 however the gold, and the silver, the brass, the iron, the tin, and the lead, 23 everything that may withstand the fire, you shall make to go through the fire, and it shall be clean; nevertheless it shall be purified with the water for impurity: and all that doesn't withstand the fire you shall make to go through the water. 24 You shall wash your clothes on the seventh day, and you shall be clean; and afterward you shall come into the camp."