I waxed my car for the first time a few weeks ago and didn't notice I got some on my grey plastic sills until a week later when I noticed the excess wax had turned into whitish smears. When I washed the car, the wax didn't come off with the detergent and sponge. So I started freaking out until I tried using some Simple Green to clean the sills. Worked great and easily got it all off. Give it a try next time if you have excess wax on your plastics.

 

Be careful not to get the simple green on the paint. Heard some horror stories that it ate through clear coat. Try warm soapy water next time.

Limited Edition Twilight Blue / Premium / Graphite / Xenons

 

I konw G35Lin had the same problem.. I would ask him for a resolution.

..pestilence..

 

I had read in I think Motor Trend about a trick for this. Ironically, I know for a fact it was the same issue that rated the G35 over the BMW 3-series. Yeah!!! Anyway, my fiance's Volvo had the same problem - white wax marks on the plastic molding and it looked like crap. So we tried their trick which is this - rubbing alcohol. I used an old toothbrush to get into the grain and after repeating the process once or twice, voila! No more wax. Hope it works for you too!

 

Check this site out, they have some tips.
Click Here.

Merlin.