Add all of the above ingredients to the 1# coffee can. Put the lid on the coffee can and secure with duct tape. Place the 1# coffee can into the 3# coffee can. Surround with crushed ice and rock salt and place the lid onto the 3# coffee can. NOW....... have the kids sit on the ground and gently roll back and forth 3 to 4 feet apart. Roll for 8 to 10 minutes. Check to see if the ice cream is hard; if it isn't, replace the lid, add more ice and rock salt. Roll for another 8 minutes. Remove the lid to the 1# can and serve into 4 good size bowls and let the kids watch the adults eat it! (or 8 small bowls and all can share).