"Say, I have been told about a real good insulator cleaner and have given it a good try. It's real good, too. Put out by the Amway Company, not sold in stores, is sold such as Rawleigh Products, Avon, etc. Name is Redu. It is put out for a rust & stain remover to be used in laundry. Mix some with water in a plastic bucket and let insulators soak at least overnight, a couple days are better. Then wash and rinse good in clear water. Even the black train smoke washes right off with no steel wool scouring. Doesn't affect my skin any, but may for someone that's troubled with strong soaps and bleaches, etc."