How to repurpose a beer keg?

Hey all. I just scrounged a large steel (not aluminum) beer keg. The web says it's stainless steel, which gets my gears turning.

I'm not sure what the internals look like, or if any coatings are on the inside.

I thought I might cut the top out and use it as a "copper" -- akin to the Victorian era device for hot water and cookery. Of course I might also be boiling invasive weeds for my compost, distilling water, or steaming batches of grain for dog food.

Thoughts? Anybody done this?