http://www.properautocare.com/2052605.html
^-- this stuff is WAY to abrassive for my black s2k. I tried some-- had to remove the scratches with "Scratch Out" (Yellow Bottle from Autozone). It was only $4usd, so I thought I'de give it a try. I hate it. 0 outta 5 stars.

-- Aaron

 

I used it cuz I read another person had a good experience with it getting out scratches from the rear window, but it didn't really work on my scratches on the rear window. Yeah, not the best stuff, maybe...2outa five stars.

 

I dunno about using it on the plastic back window-- but based on its abraviseness on the paint-- I wouldn't advise it. I do NOT like this product at all.
-- Aaron