I'm amazed that so many people don't seem to have come across proprietary brands of foot deodorant sprays.

To those who say "my feet stink - keeping shoes and socks on just makes it worse", the reply would be "Well, if they stink, for heaven's sake don't just talk about it - do something about it. Try one of those sprays." It would be a courtesy to others. (And yes, the sprays do work through your socks.)