Canning lids are essential components used in the food preservation process known as canning. They create an airtight seal on jars, preventing spoilage and extending the shelf life of preserved foods. Typically made of metal, these lids come with a rubber gasket that helps ensure a tight fit when heated during the canning process. When using canning lids, it's important to choose the right size for your jars, as they come in various diameters. After each use, lids should not be reused for canning, as they may not seal properly. Instead, they can be recycled or repurposed for other crafts or storage solutions.