I have an 05 Equinox. The exterior window belt rubbers will not come clean. I clean w/ APC, I can wipe a million times - the towel is as black as the first time. Tried denatured alcohol... same. Tried a little mineral spirits and yes, still the towel is black. I then just tried applying Poor Boy's Trim Restorer - Towel keeps turning black and the rubber has NO sheen whatsoever. Is the rubber oxidized so badly it will not clean? Any suggestions? Some kind of dye or something? HELP!