[euro_zx5]

Try Meguiars PlasticX, and if that doesn't help then consider a stronger abrasive. I usually have some PlasticX in my trunk, I can help buff it out on the 24th if you want.

I thought you were a clean freak? I must be worse off than you, I would have noticed such damage. Quarterly, I buff and polish the headlights, fogs, and taillights to prevent oxidation, and I have yet to see my parent's 94 Escort head/taillights go yellow as it gets the same treatment (almost :P ).