Numbers 31:22

20You shall purify every garment, and all that is made of skin, and all work of goats’ hair, and all things made of wood.”

21Eleazar the priest said to the men of war who went to the battle, “This is the statute of the law which the LORD has commanded Moses.

22However the gold, and the silver, the bronze, the iron, the tin, and the lead,

23everything 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. All that doesn’t withstand the fire you shall make to go through the water.

24You shall wash your clothes on the seventh day, and you shall be clean. Afterward you shall come into the camp.”