I was a surveyor for over 25 years working outdoors in all kinds of weather. My feet would sweat terribly when walking from station to station, and then would freeze while standing behind the instrument. I found that spraying my feet with an anti-perspirant, using a light silk sock and then a heavy wool sock in my felt lined pac boots helped a lot. I made it a point to stand on a 2 foot square of blue board foam insulation when behind the instrument, and in the real cold I wore a pair of boot blankets over the pac boots with a few of the chemical hand warmer packets inside the boot blankets. It seems like a pain, but nothing is more miserable than cold feet, and these remedies helped me thru some really cold jobs.