And now that it's summer, there are bound to be a few of those here and there.
I like this better than the ones available for sale because the slushy consistency lets it contour around an injury. And there are only two ingredients, one of which comes out of your faucet.
2 cups of rubbing alcohol and 6 cups of water in a one-gallon zip-lock bag. Freeze. This is great for knees, backs, and large injuries.
3/4 cup of rubbing alcohol and 2 cups of water in a one-quart zip-lock bag. This size is great for hands, elbows, and child-sized injuries.
A few hints: