Plexus is what I use to clean mine.
To remove scratches and/or fogging, well, I haven't had to do that yet on my Jeep. On the other hand, we've got the same sort of plastic windows around the cockpit of my dad's sailboat. When they get too scratched/fogged up, we break out a soft cloth and some toothpaste (be sure it's paste and not the gel stuff, and I've avoided any with 'whitening agents' in them as that might cause worse fogging). Lay a towel down on a hard surface, lay the window down on top of it, squirt some toothpaste on it, soak your soft cloth then squeeze just enough water out so that it's not dripping everywhere, then start polishing. Rinse it off and check your work every so often - you don't want to polish away more of the plastic than you absolutely have to. It's a little tedious, but you can remove most of the fine scratches and pretty much all fogging that way.
If the fogging was caused by exposure to certain chemicals, and the exposure penetrated all the way through the plastic, well... then you're sorta screwed. Other than that, you should be able to get your windows nice and clear again.