Got kind of a wierd question. anyone have a special formula to clean off the black buildup that likes to coat the inside of diesels. I bought a blazer a while back and i think the last guy who had it liked to drive it with the rear window down all the time because the all the new seats and apoulstry in it are evenly coated with back soot. I've tried a bunch of things, like car wash soap, Dawn dish soap, windex, none of them seem to remove it. any ideas?