baking soda. if your skin is too sensitive to handle it directly, you can soak your foot in a solution (no real amounts, just make it strong... baking soda is cheap anyway).
Baking soda creates an environment that fungus cannot grow in.
In combination, try to keep cheats to a minimum or go without them until it is gone... specifically VLC or ZC. Even with creating a hostile external environment, it can survive as long as it's fed, and it survives on sugar.