I found this stuff called Plexus, it is a plastic cleaner and oh my god is this stuff good for the back windows. My back windows were hazy and dull and I tried the Meguiars system and hours later no real improvement so I got some other stuff and nothing worked till I tried Plexus. Spray it on get a soft cloth wipe it off and you will have crystal clear windows again. Give this stuff a try it took me about 5 minutes to get new window results.