Instructions for use: After your jars have been filled, processed, cooled, washed and dried, simply unscrew the lid, drop a topper inside and re-screw the lid onto the jar. Canning jar toppers serve the purpose of a label by identifying and decorating your canning jars. They are environmentally friendly because they are recyclable, compostable, and reusable. They are not designed to be permanent, although they will last indefinitely if not allowed to come into contact with water, oils, or other food ingredients.