Dropping a top with dusty/dirty rear plastic window
 

Aside from actually washing the vehicle, what do you guys normally do to prevent scratching in this case? I would think sticking a towel when there is dirt in the windows would also scratch.

Also, my rear plastic window is making a really nasty crease when folding down. The "boxster chop" doesn't really help as the crease stays. It basically looks like the window is folding in half with a stress point in that area. Can anything be done here to release that stress point?

In my convertibles with plastic windows I always have a plant spray bottle full of water and a clean towel in the trunk. Every time before dropping the top I clean the window with water and a soft towel. Never Ever wipe the window with a dry towel.
The windows in my 25 year old top on my TR-8 still looked like new with this method.