I would not recommend the use of a clay bar on plastic. Their is a verrrrry good chance of scratches occuring quite easily. This may sound stooooopid, but try WD-40 on a rag. It removes tar and bugs really well and its a lubricant so it does not promote friction which is what will scratch. Then get yourself the Expel light kit. Its easy to install and the crap washes off really easily. It will protect those expensive lenses from the chips also. Their is also a company that you can send the lenses to and they will buff and polish them to a factory new finish the applt the scotchcal film for you. If you need replacement I would recommend the after-market tinted ones as they are like 600 bucks for a pair compared to 1200 each at the dealer.