The "problem" I see is that many do-it-yourselfer's use paper toweling and an ammonia-based window cleaners and clean their dusty instrument cluster/gauge face clear plastic lens/covers while doing the glass windows. Obviously this is a bad combination for polycarbonate plastic because it is somewhat softer as compared to glass. It's just difficult to educate do-it-yourselfer's not to do this as it's done in ignorance and the lack of having dedicated plastic-cleaning chemicals in their car-care cleaning arsenal and cleaning methodology. Most just want somewhat cleaner instrument cluster lens, and while getting the job done, also damages (scratches) them from repeated cleanings done in this fashion.
I use the plastic cleaning/polishing twins from Meguiar's ,#17 for cleaning, and then #10 for polishing on a window-cleaning short-nap MF. I also have Plexus, which works well for general cleaning on lens that aren't too badly scratched. I spray Plexus onto a window MF and not directly on the plastic and wipe in a circular motion.
That leads me to another condundrum of polishing fake-wood plastic panels. I use the same techniques on them, but after reading this discussion, I may have to change my use of chemicals and techniques.
