Leviticus 13:51-52

On the seventh day he must look at the mildew again. If the mildew has spread on the cloth (either woven or knitted) or the leather, no matter what the leather was used for, it is a mildew that destroys; it is unclean. The priest must burn the clothing. It does not matter if it is woven or knitted, wool or linen, or made of leather, because the mildew is spreading. It must be burned.