Both my previously owned 94 and my current 97 had a problem with the headlight covers discoloring. Both cars were low mileage and both had a yellow checkering over the entire assembly. I read on this board several times that it could not be fixed. I tried several times with a plastic rubbing compound to clean the covers, however, it did not work.
Just recently I became serious. I used a 20,000 rpm die grinder with a 4" loose buffing wheel. Once the coating is removed with the "loose" wheel you switch to a string wheel. I also used a solid stick style buffing compound. I bought both from Eastwood Company. It is not easy and you have to use a compressor with sufficient capacity. If you cannot maintain 90 psi it won't work, or it will take too long. All I can say is you can get the lens looking close to factory original.
It appears that the coating is some sort of clearcoat to protect the lens, however, something chemically attacks the coating and discolors it. Once you are thru the checkered clearcoat you will see the actual headlight cover. The reason I say chemically attacked, both, of my cars were low mileage and low sun.
Just recently I became serious. I used a 20,000 rpm die grinder with a 4" loose buffing wheel. Once the coating is removed with the "loose" wheel you switch to a string wheel. I also used a solid stick style buffing compound. I bought both from Eastwood Company. It is not easy and you have to use a compressor with sufficient capacity. If you cannot maintain 90 psi it won't work, or it will take too long. All I can say is you can get the lens looking close to factory original.
It appears that the coating is some sort of clearcoat to protect the lens, however, something chemically attacks the coating and discolors it. Once you are thru the checkered clearcoat you will see the actual headlight cover. The reason I say chemically attacked, both, of my cars were low mileage and low sun.