99' 1.8T Headlight Lense

I have looked @ www.autopartswarehouse.com for these lenses and cannot find them here. Any other places to check other than dealer. Mine are in good condition, but have yellowed (if that is a word). I have found a chemical on the web that says it will fix this.....not sure. I have tried the 3M fine grit polishing compound and it did not work. Any other ideas here? My car is in great condition other than the lenses and the rubber on the door handles. Just trying to keep it nice.