Coffee can ice cream

The ice cream maker was developed before I purchased UCO. However, there seem to be many different ways to make ice cream without an ice cream machine. Here's a note we received today:

We used to make ice cream using 2 coffee cans. One 1# with ice cream ingredients, put inside a 3# can with ice & rock salt. "Women Involved in Farm Economics" would do it on Ag day in the some Eastern Washington Grade Schools. Did the idea for making ice cream in a ball come from any of the students or teachers?

Campfire girls use the same concept. A parent of one of the girls brought the idea to UCO. And what an idea! A little searching on the Internet has also shown people using frozen juice concentrate cans inside coffee cans and even small ziplocs inside large ziplocs. People are endlessly clever.