A mate of mine has an older E46. He was showing me today that the top of the door panel where he always rests his arm has lost it's texture slightly. That's not the problem, the problem is that the area is slightly tacky and it gets dirty very quickly. I asked him why he does not just clean it and he says that it becomes worse, more sticky if he does that. I've never seen this before. Anyone got any ideas....is there a coating or something that one can apply?