This video shows how to cook cockles, which are a variety of small clam. First, it is explained that the cockles must be first well-washed in cold water to remove sand. Cockles are only safe to cook if they're still alive; generally, they will be tightly closed if they're alive. It explained that if you have an open cockle, you can check if its alive by simply tapping the shell against something hard and waiting to see if the shell closes. The cockles are put in a dish with water and an acidic substance such as lemon juice or white wine vinegar. The cockles are closed and steamed for a few minutes until the shell opens. The cockles are then removed from the shell and served.