I use RainX on my plastic headlight lenses. Not only does it clean them, it reduces that frosty look.
Thanks for the tip!
I've been through this situation many times with today's plastic headlight lenses. While I use RainX and it does work, I find it is usually temporary.
Some of the worst headlights I've seen are on older Dodge/Chrysler Minivans, which typically get so cloudy, it becomes difficult to see at night. Also, some Nissan and Jaguar S-type headlights fog terribly, too.
I've tried many kits to reduce fogging. One kind, which includes buffing pads with an abrasive paste on them, with a drill attachment, never worked at all for me. The sandpaper & polish kits work very well at first, but the clouding appears again after a few months. Meguiar's PlastX is good at maintaining the clarity of sanded/polished headlight lenses. In my opinion, however, the only real solution is to replace the lenses with either Original or Aftermarket new assemblies. It just isn't safe to drive around with all of that light being blocked by deteriorating plastic.
Prevention is key, however. By using plastic cleaners with UV protection on your headlight, it will reduce the toll of the sun on your plastic lenses. Also, be careful not to use excessively harsh cleaners on or near the headlights. Another tip is to find those clear vinyl headlight chip guards that provide UV protection.