Okay, I am pleased to report that Mungo's formula for preventing Playafoot actually worked really well. No drying, no cracking, no fungi. . . .I was amazed, because on my last desert trips I thought my feet would fall off (or was afraid they Wouldn't) . It works so Im repeating it:

2oz extra virgin olive oil (EVOO is high acid)
8 drops teatree essential oil
8 drops lavender essential oil
4 drops eucalyptus essential oil.

I bathed my feet twice a day in vinegar water and then dried thoroughly and applied this stuff. Apparently tea tree and lavender are fungicidal. No problems.

According to Mungo it also works on athelete's foot and to a lesser degree on nail fungus.