I used to have a costume department at the school where I taught drama. We got lots of clothing donations. During the summer, the air was always shut off and after washing the carpets, the moisture left mold on some of the stetsons and leather goods. I was told to microwave the leather items and it did indeed kill the mold. You cannot put metal bits into a microwave but it was good for items that could fit in the machine. Some of our props like paintings were musty smelling and I didn’t want to risk ruining the paint so I took them outside in the sun, sprayed them with colloidal silver on both sides and that seemed to do the trick. Hope this is helpful.