I've had good luck using the combination polish/cleaners that have a petroleum base. Not as aggressive as rubbing compound (I'd try the fine polishing compound and then rubbing compound).

__________________
Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html