Leviticus 13:53-55

53But when the priest reexamines it, if the mildew has not spread in the fabric, weave, knit, or leather article, 54the priest is to order the contaminated article to be washed and isolated for another seven days. 55After it has been washed, the priest is to reexamine it, and if the mildewed article has not changed in appearance, it is unclean. Even though the mildew has not spread, you must burn it, whether the rot is on the front or back.