My ally trim around the windows seems to be oxidised and less than shiney. Is there any way of cleaning these. I have tried some metal poishes and it seems to do nothing. Also one of the triangular mirror black inserts in the back door (A6 Avant) has gone rusty (bubbled and some surface gone). Can these be repainted or touched up or would I need a replacement? If so where would I get these from or is it many trips to breakers yards. Thanks in advance.