Has anyone got any advise for cleaning the alloy wheels on this 84 760, they have blackened are not cleaning up decently. I have tried to clean small test areas with no luck, it gets a little cleaner but still not bright. Have tried mild detergent cleaners, wadding polish, turtle wax wheel cleaner, and Maguire's products with no success. The paint on this car is nearly flawless, but the dirty wheels make it stand out somewhat. I know since they are coated wheels that anything abrasive will temporarily clean them, but then will be a nightmare to maintain after that...