Wrapping leftovers is an important part of food storage and preservation. The most common materials used for this purpose are Saran, FOIL, and Aluminum FOIL. Saran is a brand of plastic wrap that is used to cover food items and keep them fresh. FOIL is a thin sheet of metal that is used to wrap food items and keep them from drying out. Aluminum FOIL is a thicker version of FOIL that is often used to line baking dishes and pans. All three materials are effective at keeping leftovers fresh and can be used interchangeably depending on the needs of the user.