i haven't used it before, but novus is made specifically for repairing fine scratches in plastic/acrylic.
http://www.novuspolish.com
http://www.novuspolish.com
Removing fine scratch marks from VPI plinth
I've searched the forums and haven't found a thread on this much to my surprise. Just wondering out there how VPI owners of the acrylic plinths of the Aries series tables and the HRX's clean their shiny black plinths and remove those hairline surfaces scratches that can accumulate over time.