In this video, I'll show you how to boil water using a fire bowl as per the Leave No Trace principle of minimizing camp fires.
I had learned red this at my local search & rescue. You get yourself a cheap stainless steel mixing bowl or something that will fir in your pack.
You will need your cup, multi-tool and lighter.
The idea here is that you don't need a lot of fuel to prepare hot liquids in an emergency situation. Also the spot where you are might not be suitable for campfires. This method minimized the impact.
I used several branches of dead wood from my backyard and a bit of spruce. You should be able to break off the smaller twigs with your hands. This also applies to pencil sized branches. If you can't break them, then they wood might be too wet.
Larger pieces can be cut using the saw on a multi tool. THe multi tool can also be used to handle the fire bowl and cup without burning yourself.
It is a good idea to stabilize your fire bowl.
I used a piece of dried birch bark to get the fire going. Once you get a nice bed of embers, you can simply lay the cup on top of it. The fire bowl should burn the wood clean and you are left with white ash.
Once everything is cooled, you cam simply disperse the ashes; leaving no trace.
Learn more about this leave no trace principle