On my K1 I had a couple of spots where the white paint had chipped off from the tank badges. I fixed it with nail polish. Cheap, glossy finish and pretty convenient to use. 8 years and counting.
In fact, I used nail polish to completely paint the CB350 badges. As it takes a while to dry, if you apply a generous layer you can get that "enamel" finish. Just have at hand cotton buds and polish remover in case you take the brush out of the desired area.
I use black nail polish quite often to touch up scratches and the like in part such as frame, seat pan etc.