I'm still pondering an idea to use the cut off at the top stainless steel hip flask for my PSK. It's very pocketable, the vertical design is better for boiling compared to flat cans, and it's much stronger than tin cans.

The problem is - I want to keep the flask function too. So, I'm stuck with the resealable lid design. Don't know how to make it watertight and at the same time able to withstand the high temperature of fire.