The upside down in the snow trick is a good one when camped. I suffered two frozen nalgene bottles before I learned to keep them from freezing. It was a dire situation. I still don't like the possibility even though its preventable. Besides, I'm going back to wineskins for reasons of nostalgia. But it is hard to find them nowadays. Candian Tire doesn't seem to carry them anymore. I'm thinking of making on using a Nalgene canteen. Shapes a little awkward.