Just wondering if anyone has tried using the little HDPE Nalgene bottles as mini boot warmers for the morning? I was thinking you could fill these with boiling water and drop them in your frozen boots in the morning to take the chill off?

I know they are more weight, but I love the chemical hand warmers. I slept with one in each sock overnight. Then, about 4am I stuffed another pair into my ski boots with some socks. They warmed up the boots enough by morning (the packets do require some humidity to work, so you have to "start" them in your sleeping bag).

The nice thing, is then I kept them in my gloves all morning while I did camp chores. That was really nice. I found them most useful when I had to keep taking my gloves on and off to start the stove, tie my boots, etc. I don't know that the hot water bottles would keep their temperature overnight - but maybe if you had a gigantic thermos or something like that.

I love the chemical warmers as well and use them exactly as you do (amazing how good it feels to warm the hands after pumping those freezing stoves eh?) For the bottles, I'd just throw them in when I first woke up and let them warm the boots while I make breakfast etc. I wouldn't expect they'd totally warm them up but just enough to take the edge off :)

I do it with half liter bottles...