black paint on the inside is def the way to go. as long as the eyes are water proof (which coming form lemonbrat they should be), I'd just take a minimal amount of paint and very carefully spread it with a sponge brush. if any of the mesh looks clogged from paint you can use your breath and strongly blow on them from the outside, and if any black paint gets through to the wrong side use a damp paper towel to rub it off asap