Numbers 31:23

20 And every bit of clothing, and anything made of leather or goats' hair or wood, you are to make clean.

21 Then Eleazar the priest said to the men of war who had been to the fight, This is the rule of the law which the Lord has given to Moses:

22 But gold and silver and brass and iron and tin and lead,

23 And anything which may be heated, is to go through the fire and be made clean; but in addition it is to be put in the water of cleaning: and anything which may not go through the fire is to be put in the water.

24 And on the seventh day, after washing your clothing, you will be clean, and then you may come into the tent-circle.

25 And the Lord said to Moses,

26 Get an account of everything which was taken in the war, of man and of beast, you and Eleazar the priest and the heads of families of the people: