Leviticus 13:53-59

“But if the priest examines it and finds that the contaminated area has not spread in the clothing, the fabric, or the leather, the priest will order the object to be washed and then quarantined for seven more days. Then the priest must examine the object again. If he finds that the contaminated area has not changed color after being washed, even if it did not spread, the object is defiled. It must be completely burned up, whether the contaminated spot is on the inside or outside. But if the priest examines it and finds that the contaminated area has faded after being washed, he must cut the spot from the clothing, the fabric, or the leather. If the spot later reappears on the clothing, the fabric, or the leather article, the mildew is clearly spreading, and the contaminated object must be burned up. But if the spot disappears from the clothing, the fabric, or the leather article after it has been washed, it must be washed again; then it will be ceremonially clean. “These are the instructions for dealing with mildew that contaminates woolen or linen clothing or fabric or anything made of leather. This is how the priest will determine whether these items are ceremonially clean or unclean.”