Hello, Ride a slk r170 in blue. Have the car washed today by hand and applied wax. At the rear wheel run the paint has become stained. Have everything washed again but the stainy remains. The places feel rough in contrast to the rest of the paint and look dull. Can you get this away with a polish again? Can anyone tell me what I did wrong? Have used extra microfibre cloths and washed with the two bucket method.