Leviticus 13:54-56

Amplified Bible

⁵⁴ then the priest shall order that they wash the thing in which the mark occurs, and he shall quarantine it for seven more days. ⁵⁵ The priest shall examine the article with the mark after it has been washed, and if the mark has not changed color, even though the mark has not spread, it is unclean; you shall burn it in the fire; it is a corroding mildew, whether on the top or on the front of it.

⁵⁶ “If the priest looks and the mark has faded after it is washed, he shall tear it out of the garment, or the leather, or out of the warp or woof.