I don’t have any suggestions about cleaning. A lot of the farm cats got ringworm five years ago, and also gave it to me (I in turn gave it to my sisters…we were always told to share ;))
What we do at the shelter is spray the cats with Vetericyn.
Home
“Vetericyn works quickly to care for infections or open wounds. In addition, it is safe as water so it will not harm your cat or the environment. Cats typically lick their injury so any products applied should be non-toxic. Vetericyn is non-toxic so it will not cause injury if it happens to be ingested or licked after application. This is possible because Vetericyn works in the same way as your cat’s immune system. As such, the body recognizes it as a friendly infection-aiding ally. Vetericyn also creates an optimal environment for healing.
Vetericyn used on wounds have demonstrated a reduction in healing time by up to 60%. Vetericyn significantly increases the oxygen content at the wound site within 30 seconds and maintains that oxygen level for up to 36 hours. This increase in oxygen along with the reduction of infection is responsible for these accelerated healing times. As a one-step cleanser and dressing, it eliminates the need for multiple products while reducing the application time and requirements.”
The cats that I have seen that were treated with Vetericyn healed much faster than those on any other ringworm medicene. It can be used for ringworm treatment, as well as other things (Hot Spots, Rain Rot, Rashes, Post-Surgical Sites, Burns, Cinch Fungus, Ring Worm, Skin Infections, Scratches, Eye Infections, Cuts, Skin Ulcers, Thrush and Insect Bites).
That is probably way more information about treatment than you wanted, but I thought I would put that out there. I hope your cat gets better soon!