To me it seems like a bad idea to put anything on ring worm externally, without taking something for it internally, too. I'd be afraid it would just drive them deeper into my body, where they'd hide out for a while, then surface again later. Here is why I think so:
I was taking significant amounts of Green Black-Walnut Hull, Cloves and Wormwood for intestinal parasites. While I was taking it, two ring worms showed up on my leg. One was near my ankle, another was by my knee. I think the surfaced from deep within my body. I kept taking the GBWH/CL/WW and a few days later, a huge rash broke out on my back. It looked like the photos I've seen of big ring worms. It took two months to get rid of the rash. I kept taking the GBWH/Cloves/WW while putting Apple Cider Vinegar on the rash. The spots on my leg still itch from time to time, so I don't think I've got it all out of me yet. I plan to do routine maintenence with the GBWH/Cloves/WW.