I know there were a lot of threads on how to clean this, but I found another route. Since my car is black/black, I didn't like the grey cloth under the rear window. So I bought some fabric dye and some sponge brushes and re-did it black. Came out pretty good. Not going to win any concourses, but I like the black better. Don't know how well other colors would work. The black seems to cover and dry opaque.