I'm pretty careful so I don't get many scratches. I prefer to coat them, with nail polsih or crazy glue. Wax is excellent also, but it has the disadvantage of being a release agent for other possible coatings. If I use wax, I try to keep with simple waxes like beeswax, which is amazing. A lot of commercial products can have stuff in them that are a lot harder to remove like silicones.