For this reason, you should always put a coin in your freezer

The Role of Freezer Organization in Power Savings

The circulation of cold air is also better in an organized freezer. Keeping the freezer stocked also means low temperatures last longer when power is off. Coin-in-the-freezer trick will be most effective in a well-organized freezer because there is little chance of the container being knocked over or lost amongst the contents.

You should place the container holding the coin in a location in your freezer where you will easily notice it. In this way, the coin does not get out of sight or out of mind as you use the freezer.