I used scratch X on mine and it worked pretty damn well!

 

Hey, I've been gone for a while, long explanation, but between my TT and my MKIV Supra, I have had great sucess with the plastic polish like achTTung had suggested. I used to use this stuff I got from JC Whitney for my Jeep windows in the soft doors etc, and it worked fantastic. After you have corrected the problem, or before the problem starts, I recommend the following: 3m makes a protective clear film that you can cut to the shape of your headlights that not only withstands scratches, but also is a good chip delfector from all the stone chips that you coould end up with. Think about this...my Chevy Truck which has over 200k highway miles looks like it has been through a sandblaster....this 3m product will totally prevent this problem. Look at the following link:

http://rds.yahoo.com/_ylt=A0oGkmqFJ0...er/output_html

This stuff works!