Dry baking with inner baking pan (ex tuna can)

For small cans like that, I usually just burn them out. Then scrub them with a scrubbie to get rid of the plastic residue.

Dry baking on the trail is sort-of an art form. You can do it but it can cost a lot of fuel (unless you use a wood fire) and it can damage an aluminum pot.

With Ti, it works well enough. But only small portions at a time. Better is to simply steam bake stuff (though this leavs most surfaces wet/sticky.) For example, bisquits come out good, but are wet and not browned. They tend to stick to the inner can. It is easier to use a piece of aluminum foil. After cooling this can be peeled off provided you coated it with olive oil.

If you hang out in kitchen shops and look at specialty baking, you can find mini tins for baking in. These are designed for it.

Also, look for brands that don't use liners if you want to use cans. They do exist.