Numbers 31:21-23

21Then Eleazar the priest said to the men of war who had gone to the battle, “This is the ordinance of the law which the Lord commanded Moses:

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

23everything that can endure fire, you shall put through the fire, and it shall be clean; and it shall be purified with the water of purification. But all that cannot endure fire you shall put through water.