The way they taper down on the inside tells me that they can only be used to boil water. I need a container that I can boil soup in and won't have any trouble cleaning out. Also, I need my container to have an opening big enough to spoon from, and also big enough to store some things in when not in use. I don't like the idea of empty space in my kit.
I am designing my own compact wood gas stove that will accomplish all I need in a cook kit, and serve as storage for when not in use.