spraying clearcoat on them will make them go to shyt faster. you are better off sanding them, buffing them to a glass finish, and waxing them as often as you wash the car, what does it take to wax a pair of headlights, 3 minutes???? i have sanded and buffed 17 million headlights in the last 10 years and have yet to see one turn yellow again. i mean think about, how old is the average mark VIII? it took that many years for the headlight lenses to look like shyt, so why would sanding one and buffing it make it turn yellow any faster? it wont, it will take many years to make it look bad again.
Catmech just bought some first gen hid housings and sent them to me to " fix up" it looked like someone had sprayed clearcoat on them sometime in the near past, i wish i had taken before and after pics, because all i did to the lenses was wet sand and buff them and they look mint, i did have to rechrome one housing inside though. just sand and buff, dont spray clearcoat on them.