Now that gardens are producing, food preservation supplies are disappearing off store shelves. Canning lids are few and far between. But remember, do not reuse canning lids! Do not use old, dented, or deformed lids, or lids with gaps or other defects in the sealing gasket. When jars are processed, the lid gasket softens and flows slightly to cover the jar-sealing surface, yet allows air to escape from the jar. The gasket then forms an airtight seal as the jar cools. Gaskets in unused lids work well for at least 5 years from date of manufacture. The gasket compound in older unused lids may fail to seal on jars.
By: Ashley Svaty