ironraven,

Have you ever tried it? I haven't done it with a Nalgene bottle, but I have seen it done with canvas containers that could also not be placed over flame.

I don't think there is any chance in he__ that the rocks are going to melt the nalgene when you drop them into water. Is the process the most efficient? Heck no! But if you are trying to boil water in a Nalgene bottle, chances are your circumstances are far from ideal. Survival is about improvisation.

Tell you what, I have an older bottle that the lid doesn't completely seal on. I'll actually try it and report back. Then we will know, right?

Greg