Leviticus 13:54-59

54 then the cohen is to order that the article having the infection be washed and isolated for seven more days.
55 The cohen is to examine it after the stain has been washed, and if he sees that the stain has not changed color, then, even though the stain has not spread, it is unclean; you are to burn it up completely - it is rotten, no matter whether the spot is on the outside or on the inside.
56 If the cohen examines it and sees that the stain has faded after being washed, then he is to tear the stain out of the garment, leather, threads or woven-in parts.
57 If it appears again in the garment, threads, woven-in parts or leather item, it is contagious, and you are to burn up completely the article that had the stain.
58 But if the infection is gone from the garment, threads, woven-in parts or leather item that you washed, then it is to be washed a second time, and it will be clean.
59 This is the law concerning infections of tzara'at in a garment of wool or linen, or in the threads or the woven-in parts, or in any leather item - when to declare it clean and when to declare it unclean.