


Car accessory shops here sell stuff called T-Cut, which is a very fine
cutting paste for paint, and this will remove the dull finish and
minor acratches. It will also remove all the traffic film and stuff that
you probably don't realise is there, and give your paintwork its original
lustre and shine. It can sometimes react badly with metallic paint, though,
so try it out carefully before going to town with the stuff. Afterwards
apply wax polish, and all will be well again.

BTW - don't confuse T-cut with the cutting paste used for grinding in 
valves...the principle's the same but the coarseness is vastly different...