Leviticus 13:54-59 NIV

54 he shall order that the contaminated article be washed. Then he is to isolate it for another seven days.
55 After the affected article has been washed, the priest is to examine it, and if the mildew has not changed its appearance, even though it has not spread, it is unclean. Burn it with fire, whether the mildew has affected one side or the other.
56 If, when the priest examines it, the mildew has faded after the article has been washed, he is to tear the contaminated part out of the clothing, or the leather, or the woven or knitted material.
57 But if it reappears in the clothing, or in the woven or knitted material, or in the leather article, it is spreading, and whatever has the mildew must be burned with fire.
58 The clothing, or the woven or knitted material, or any leather article that has been washed and is rid of the mildew, must be washed again, and it will be clean."
59 These are the regulations concerning contamination by mildew in woolen or linen clothing, woven or knitted material, or any leather article, for pronouncing them clean or unclean.