I have painted between my toes with tea tree oil, and darned if it don't work pretty darned well. Often, just a single application prior to bed, and by morning no hint of any itching.
Twice now, I have soaked my feet, toes mostly, in a potassium metabisulphite solution (one tsp per liter of water) to nip athlete's foot. After an eight minute soak to let the compound invade my skin, pat dry, and the results have been very good. Tea tree oil on the infected follicles works very well.
I add a drop of dish detergent in the bisulphite to help it to break skin surface tension (especially important in the oily scalp), and soak a clean face cloth in the solution. Drape over your hair and work the solution into the scalp. Wait several minutes for absorption, and then rinse well, dry thoroughly. Don't wear hats or toques for a few days. Works for me.
Bisulphite is lethal to spores, molds, viruses, and to bacteria.