How to clean / polish instruments cluster lens?

Beware of windex. I cleaned an old 65 taillight lens with that and it crazed before my eyes! I dont know what was in that bottle but it was like watching something ice up in fast motion. very strange......could have been crazed before but invisible and this stuff got in the cracks and made them visible?
Hmmm.
Food for thought, thanks!
I have never had it happen to me, the crazing I mean of course.........