Headlights lens are made out of plastic and eventually the UV will make them yellow under the sun. After about 9 years of service, the headlight has develop a yellowish tint. It's actually worse than it appears on the photo. For some reason, its barely noticable on the photo
Because the yellowing isn't all that bad, I decided to remove it using some cleaner wax. This seems to work out pretty well.
I then apply the coating with some microfiber cloth and buff out the excess. It comes as a liquid and is clear. We shall see if prevents yellowing. It's a rather expensive product, so I hope it works.