In the smaller coffee can combine ingredients and stir well. Put lid on tightly.
Place a thin layer of crushed ice on the bottom of the larger can. Sprinkle with
1 tablespoon rock salt. Place the small can inside the large can. Pack area between
the cans with crushed ice and rock salt, using 2 tablespoons rock salt for every
cup of ice. Put the lid tightly on the large can. Roll the can back and forth 10
to 15 minutes on a countertop or floor.
Lift out smaller can and carefully remove the lid. Scrape down sides and stir
well. If the ice cream is too soft, repack the large can with fresh ice and rock
salt. Replace the lid. Roll it back and forth for a few minutes more or until the
ice cream is firm.