But the fingernail paint, as purehavoc mentions, may do as well & easier to get. I've also heard of using model airplane paint or auto touch-up paint. One hint, dip a toothpick in the paint & apply it with that. You can pinpoint where it goes a lot easier than with a brush.
I have always used fingernail paint as well. I get the brightest neon colored paint I can find ad just touch them up as needed. It won't glow in the dark but in low light situations they do reflect a little bit of ambient light, enough to see your sights quickly as long as it isn't pitch black outside.
I like fingernail polish for sights. If the sight is smaller than you prefer it's pretty easy to put a globe on top of it. I have the best luck with Lee Hard as Nails. I have never tried fingernail polish on a safety. Fingernail polish is so thick I can see a lot things going wrong when used on a safety.
I have the glow-on and it works alot better than most of the lumenicent stuff out there . but again its just ok stuff their decals work better and longer but that stuff is thick and its hard to cut small stuff and work with it