Two years ago I watched this Dr. OZ show, he was presenting this young lady who said her feet are always sweating and smelling even when she lives in Calif. and wears sandals. Dr Oz told her to make a black tea infusion (normal black tea) the stronger the better and soak her feet in it, Warm or cold it doesn't matter, twice a week for 20 minutes.
I did that, since I had sweaty and cold feet. Mine were always sweating but in winter it was worse; and this infusion really changed everything. Since then I have NEVER had sweaty feet or smelly feet again. What works in the tea is the tanic acid. It is a life saver. I really was red faced before when I had to take my shoes off.