My horse has had two small bouts of rainrot in the time that I have owned him. What I did which worked extremely well was to bleach all my brushes after every time I brushed him. To treat the actual rot, I used a small diluted amount of betadine (please anyone, if this is not safe, please let me know), antibacterial/antimicrobial shampoo mixed with lot of water and spread it over the scabs, scrubbing with a stiff brush. The scrubbing loosened the scabs and really killed a lot of the bacteria. Then, while the scabs are still wet and soft, I gently pulled them off of my horse. Lastly, I applied a small amount of MTG directly to the affected areas. This protocal usually only had to be repeated for a few days, and everything was all cleared up. Hope this helps.