The box must be first cleaned with cold water. To improve the insulation within the box, you can also add a small amount of salt here. After that, you can add objects to the box, and to assist keep the temperature inside the box stable, you should place some ice blocks or crushed ice on top of the contents.

First, clean the ice box with cold water. When the box temperature reaches normal, use a mild detergent and warm water to wipe down the interior and exterior of the ice box. If the ice box has a build-up of ice, periodically thaw and clean it thoroughly to prevent ice accumulation, which can affect its cooling efficiency.