Great post. I've seen even detailing shops using similar technique even on clear coat paint, so I don't think it creates hairline scratches either. Cleaning the headlight from a inside involves more work. You need to 'bake' the headlight to a certain temperate to separate the front plastic from the rest of the case. And when you put it together you have to make sure you put it back and properly and seal it with a good adhesive - otherwise water will get inside. Or if you just have dust, I think you can pull out the electrically and wash it with shampoo without taking it apart.