Some people put leftovers from the table in a canning jar and process it long enough to seal the jar. This is not safe. It IS safe to can spaghetti sauce and stew but only from tested recipes. Some foods cannot be canned because it is impossible for the center of the food to reach high enough temperatures to destroy bacteria. Thickened stews and mashed potatoes are examples of foods too thick to can.
Guide sheets for home food preservation can be found at http://extension.missouri.edu/publications. The National Center for Home Food Preservation’s site is http://nchfp.uga.edu.
Contributors: Tammy Roberts (660-679-4167) and Susan Mills-Gray, Nutrition and Health Education Specialists, University of Missouri Extension