Hotonics not only makes boot heaters (use 'em, love 'em) but also SnapDry boot dryers (also use 'em, love 'em).
The Snap Dry has a fan and blows warm air into the boot - sticks right down into the boot at a right angle bend to direct the air toward the toes (or can be adjusted to direct the air anywhere you want).
Here's my routine:
(a) Wash feet every day and smear in a very thin layer of gel antiperspirant.
(b) At the end of the day, turn Hotronics boot heaters up to highest setting and leave on until the red lights go out - then recharge.
(c) Immediately upon getting home (meaning, home, condo, motel room - whatever) insert and turn on the Snap Dry boot dryers - leave on until I put the boots in my boot bag next moring. I NEVER remove the liners.
I never have had any problem with damp boots or smelly boots.
Here's the link to Hotonics: http://www.hotronic.com/