I had about 1.5 years ago purchased Plexis to get stains out of rear window, followed directions with not very good results by following directions. Yesterday while cleaning window I mistakenly blasted the window closeup about 1/2-1 inch from window with plexis can upside down. Put a good thick gunk of plexis on window. When I wiped it off, it was clear!!! I guess I was pretty much a duh on this, but when applied and rubbed as directed, nothing much happened. It was only when sprayon is close and in excess does this stuff work. My window is now finally clear, the first time ever.

 

Just FYI, Plexus is good for everyday cleaning and maintenance. To get tough stains out, I use the Meguiars treatment. Try Meguiras #17 Plastic Cleaner followed by Meguiars #10 Plastic Polish. When I first got the S2K, the back window was extremely dirty. After one applciation fo the Meguirs stuff, it was perfectly clear. I use Plexus everytime I wash the car. just for maintenance.