I bought some "Bright Sights" paint, but was a little disappointed in the "Ghost Glow" paint they advertise. Here's a link in case you want to try it.
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.