A mixture of a litre of rubbing alcohol and 20 drops of Oil of Oregano applied in the same area is also effective.
**Actually, household bleach may clear it up, but you will end up eating away at the uninfected part of the horses hoof. Sugardine (a mixture/paste of betadine and sugar) works well along with scrubbing (with a sponge) with betadine and packing with a lyme paste (Lyme and lots of water) for the first day -- you don't want to use it longer than that because Lyme is a drying agent -- and then scrubbing with betadine and using a product like Thrush Buster or Kopertox works the best to fully get rid of it.