Like most older cars, the headlight covers got a yellowish film all over them that would not come off with normal car washing or scrubbing. Tried several buff kits, one worked, but only after 30 minutes of buffing, and they turned yellow again within a couple of months. Right before I wrecked the car, I had it detailed at the dealer and they were able to make the headlights look brand new! Unsure if the dealer's cleaner would have kept the lights clear for longer than a month.