Leviticus 13:55-57

⁵⁵Then the priest shall examine it, after the plague is washed; and behold, if the plague hasn’t changed its colour, and the plague hasn’t spread, it is unclean; you shall burn it in the fire. It is a mildewed spot, whether the bareness is inside or outside.

⁵⁶If the priest looks, and behold, the plague has faded after it is washed, then he shall tear it out of the garment, or out of the skin, or out of the warp, or out of the woof;

⁵⁷and if it appears again in the garment, either in the warp, or in the woof, or in anything of skin, it is spreading. You shall burn what the plague is in with fire.