How to prep for paint a plastic part that was waxed?

Due to the recent storms, a piece of palm scale bark landed on my wife's Camry back built in spoiler on top of the trunk. The thing is plastic painted body color and waxed.
How do I prep for painting and removing the wax? Need to make sure the paint will stick to the part. I am only touching a small part and not looking to scuff the hole thing.

 

Dawn --in heavy quantities--a couple of times --to start. Then some paint thinner -wiped off completely. That should get any wax --so what if you take wax off any other parts -- just re-wax those when done.

 

Rubbing alcohol for a small area. I always use a bit of it to clean before touching up plastic or metal. Wipe a bit on, immediately wipe it off.