If you have wax on your mirrors or door handels and find it hard to get off you can simply use a big eraser (not the kind on the end of a pencil, the eraser that is like about inch and a half long). All you would have to do is erase the wax on the exterior peice.

Another way of preventing getting wax to stain these peices is to use the same stuff you use on your tires and dress all the peices before waxing. And if you get wax on the exterior trim you just have to wipe it off that easy