My kittens have had ringworm for a while and I've been treating them.?

Well, all the spots have cleared up and the vet says "I think they're good, you have a maybe 1% chance that they still have it." He won't do a culture or use a black light to check. So after spending almost 300 dollars to date on vet visits and meds to treat these kittens, I went out and bought a black light to check for sure. I'm tired of keeping them kennelled. I'm ready to let them run free through the house. This has been a headache for me and the kittens I'm sure. So I held them both under the black light and at first saw nothing, but when I moved them closer there were a few tiny green spots that looked like dust but with a faint green tint. I'm trying to find out if this was ringworm spores or just dust glowing under a black light. ??? It just looked like dust, but faintly glowed under the light. Anybody know anything about this? Please?? Thanks!!