Welcome to the forum! Thanks for stopping by.

These are interesting ideas, but for an emergency (lost hiker, downed small aircraft) situation, they just don't seem that practical to me. I imagine that's why you don't find them in survival guides.

The lack of a metal cup shouldn't stop you from having clean water. We have discussed cup-less methods of boiling water in the forum--hot rocks in the Nalgene, hot rocks in a canvas hat--before and they can work. Or chemical treatment works fine if you have some sort of container. Of course, a hand-pumped filter is another option. Remember, "one is none". It would seem to be a good idea to carry two heat-resistant containers or have two different water purification methods available.

Anyway, like I said, interesting ideas, but they seem more suited for longer-term survival, in my opinion. And even then, their ability to kill pathogens is not going to be as good as the more common methods. Just because ancient peoples used a method doesn't mean that they didn't have to run behind a bush every 20 minutes with the runs.