Your Cooter is designed to insulate, which means it will retain heat as well as cold. For this reason, try to store your Cooter in a cool environment prior to loading it with ice. If stored in direct sunlight, a warm garage, or a hot vehicle prior to use, a significant amount of ice will be wasted cooling the Cooter itself. One way to cool the walls is to preload it with a sacrificial bag of ice or put your Cooter in the deep freeze or fridge prior to use. The starting temperature of the Cooter is one of the most commonly overlooked variables in ice retention.