The best ways to store aluminum foil when not in use include keeping it in a cool, dry place away from direct sunlight to prevent degradation. It's advisable to store it in its original box or a resealable plastic container to protect it from moisture and air exposure. Some people also use a paper towel roll as a dispenser by placing the aluminum foil around it, ensuring the shiny side is out for easy access. Keeping it in a drawer is also common, but it's important to prevent it from crumpling or tearing.