Mrs. Mercedes Benz Convertible came to me one day and asked me how to get wax off bumpers and molding.  I told her that depending on the type of wax, it could be a big problem.  I explained to her how I always mask rubber and plastic with tape to avoid such a problem, but she was past that!  A few days later I performed an exterior detail on her Mercedes Benz Convertible.  Some of the wax came off of some parts, but the front bumper and door moldings were really bad and everything I tried seemed to have no effect.  I finally ended up using a black leather dye and two months later, part way into the rainy season, and it still looks great!  You cannot tell the dyed parts from the original parts, and none of the wax bled through!  Another successful detail and a new trick up my sleeve!