Leviticus 13:57-59

57However, if it shows up again, you must burn the clothing or the leather article.

58But if the area disappears from the woven or knitted clothing or any leather article when it is washed, wash it again, and it will be clean.

59“These are the instructions for deciding whether mildew in clothing that is woven or knitted from linen or wool or in any leather article is clean or unclean.”