but would a regular old chest cooler work instead?
Old? Mine is made of metal. Works like a charm.
Boil water in the pot for an hour and it will leave an oxide layer on the surface of the aluminum. Then just never scrub hard enough in subsequent uses to remove the oxide layer.
Do this. Just boil some water, dump and turn upside down to store.
I wipe mine down with a cloth after each use (sometimes days after the fact) rinse and store upside down to keep the vermin out and its ready for the next use. It has a beautiful dark gray patina from years of use. Its not like building a clock or something.