I have a 3m clearbra on my TL. Custom sized and had my bra for over 2 years. I wax it (zaino) all the time to keep the film slick as can be.
I've used abrasive polishes with a PC and did no harm. Just make sure you don't apply too much pressure and keep the speed down to 4 or 5. I'm sure any wax will not yellow the bra over time.
IMO, I think it would yellow over time when there's so much heat and sun which will make the film fade or yellow.