SMTBs,
I gotta agree with toe, booth and kickass... (hmm, sounds like fun on the weekend eh?)
However figment...
Look at where he's from geographically. Figment, you know I love you, but you don't know squat about -10F. However, I live where that is a balmy daytime temp, so I know something about freezers.
SMTBs, stay out of the freezer. Take your lid into the little closet in the bathroom and turn on the water. I assume you know how to do that. Use any shampoo sitting around, but antidandruff stuff is not needed...well, maybe.
Do not run directly to the freezer. Towel off, and go to the fridge for a beer. Let the helmet dry naturally. You could stuff a towel into the helmet for a few hours to help.
Helpful hints...if you use a nice smelling shampoo, like the stuff your girl uses, it really smells nice the next time you put your helmet on. If you use the usual guy shampoo, i.e. Lava, it won't smell that nice.