You can also use a butane lighter to heat the lead. Heat it a little on each side (I hold it with copper wire and make six 'passes' with the lighter on each side) and then let it sit for a couple of seconds. Dip it in the powder paint and shake off the excess. Then a quick pass through the lighter to set the paint. Just be very careful to make sure they are lead and not brass - I've had brass eyes explode during the heating process. Not sure why but I suspect differential heating of the material. If you use a butane torch, do it very quickly. Those torches are a lot hotter than a butane lighter and can overheat the lead. When you dip the overheated lead into the paint, you get a big blob out that's no good to use for tying.

Another technique for painting the eyes is to put them in a shallow box and paint with Krylon paint on one side. Let them dry then give the box a shake. The heavier painted side will go down bringing the unpainted part to the top. Then paint the other side. You can even make two-tone eyes this way by using different color paint on each side.