He is to burn the fabric, weave, or knit, whether the contaminated item is wool or linen or leather. Since the mildew is harmful, the article must be burned up.
KJV
He shall therefore burn that garment, whether warp or woof, in woollen or in linen, or any thing of skin, wherein the plague is: for it [is] a fretting leprosy; it shall be burnt in the fire.
ASV
And he shall burn the garment, whether the warp or the woof, in woollen or in linen, or anything of skin, wherein the plague is: for it is a fretting leprosy; it shall be burnt in the fire.