I have an old SWR Workingman's 15 I got off of C.L. I cleaned all the pots and it sounds pretty good. The outside of the amp was covered in dirt and cat hair. I cleaned it with a stiff brush and carpet cleaner, then vacummed it thoroughly. It's clean now but it still lookes thrashed. Full of pills and rough places where it looks like a cat used it for a scratching post. Is ther anyway to restore the exterior short of replacing the whole carpet?