I have a set of light gray corbeau seats, the cloth on the seat part had some stains in them and it seems like any fabric cleaner i try to get it out with discolors the fabric. any suggestions what else to try? I have been cleaning cars all my life but never ran into this problem. I dont want tyo reck the seats any more and they are not major stains, but they look all discolored because the seats are light gray. help!