Mine didn't require much effort at all, possibly because its relatively new. But it was very hazy and dull looking. I believe Meguires makes three different products for the clear plastic. The two I mentioned in my first post and the other being Clear Plastic Polish.
The polish claims it also works on: clear plastic boat windows, motorcycle windscreens, CD's, eyeglasses, instrument panels, skylights and aquariums. Sorry, I just went ahead and listed all its uses.
At least you can get more uses than just your plastic window.
1969 280sl 5 spd
Gainesville, Fl.