Went out and tried it. Still some shadowing of the scuffs remain, but much better. You can't imagine just how dirty a seat is, until you take a magic eraser to it. Feels like it should be on the showroom floor, as a new seat. Made it rougher and tackier though, and will be more difficult to slide around on it. That is, until it gets dirty again. Thanks, copdocpvd, for the tip.