Ive been trying for ages to find something to get white wax residue off of my black trim.
Tried everything; AutoGlym Bumper Care (covers it up well, but when it wears of the whiteness is still there), meths, white spirit. Everything. Nothing worked. Almost resigned myself to having white-ish trim.
Found out today that if you use oil, yep oil, like WD40 or 3-in-1 it comes straight off.
Well, I think it comes off. Will have to give it a few days and see if it returns, but apparently it does work. Found it out from a car detailing website. Tried it out my fiancees black plastic bumpers and they now look the nuts too.