Leviticus 13:54-56

⁵⁴then the priest shall give directions, and one shall wash that on which there may have been the plague, and the priest shall set it aside a second time for seven days.

⁵⁵And the priest shall look upon it after the plague has been washed; and if this, even the plague, has not changed its appearance, and the plague does not spread, it is unclean; it shall be burnt with fire: it is fixed in the garment, in the warp, or in the woof.

⁵⁶And if the priest should look, and the spot be dark after it has been washed, he shall tear it off from the garment, either from the warp or from the woof, or from the skin.