Are you talking about reusing old jars or trying to save the product that you already canned? If you are trying to save product and seal popped and it sat on a shelf...….THROW THEM OUT!!!!! If you just canned that day then reheat the food and jars and reprocess with new jars. There may be a chip or food on the rim that preventing a tight seal. If you are trying to save money by reusing old commercial jelly/spaghetti jars.....don't. They are not made for canning and may shatter during processing.
Tranum is correct. If your in doubt them please call your county extension office. These is a strict code on how to safely can food. Its not something to play with.
Last edited by PMahowald; 07-27-2018 at 05:24 AM.