Bleach kills the fungal spores that cause ringworm when used in a 1-10 ratio, according to the University of Florida's College of Veterinary Medicine. For example, surfaces are cleaned with a solution of 1 1/2 cups of bleach mixed into 1 gallon of water.
A 1-10 ratio is a strong bleach solution, so people need to wear protective clothing, UF College of Veterinary Medicine advises. Animals must not be allowed in the area until cleaning is finished. Bleachable fabrics are also able to be safely disinfected by the cleaning agent after ringworm infestation, states Clorox. A typical laundry load needs 3/4 cup bleach added to the hottest water allowed for the fabric.