Someone told me that the juice from a green walnut hull would kill fungus like ringworm. Maybe it does, since it takes off the hide too.
Another fine idea was to substitute Ben Guey for Preparation H. Now I can sympathize with the proverbial turpentined cat. Although anticlimactic, Lotramin Ultra does a good job.
But just for the experience, talk someone else into trying Ben Guey for their rash. Sure is good for sportin' entertainment, if nothing else.