Thought I would pass along this tip from Dennis, long time cruiser, and progressively smaller boat Sailor (now in a Flicka, so not sure how much small he will go).

He gave me a tip. Ammonia, found in Windex and most glass cleaners is toxic to lexan and Plexiglas.
I think I had read this somewhere before, but he pointed out to me my port light windows (which were ok when I bought the boat) were most likely harmed by my use of Windex to clean them (and only maybe once or twice).
I have removed it from the boat.