Before reusing old canning jars, you must clean them. Canning jars, also commonly referred to as mason jars, are used to store homemade jams, jellies, pickled items and homemade canned fruits and vegetables. Storing food in a dirty container is not only unsanitary, but it can also affect the taste of the food and possibly cause mold to form in the canned food. After cleaning is completed, the jars should be sterilized.
Fill a sink with warm water and a squirt of liquid dish soap.
Submerge the old canning jars and lids in the soapy water. Use a sponge or cloth to wipe the inside and outside of the jars and lids.
Rinse well under cool running water to remove soap residue.
Towel dry the lids to ensure they don't rust. The jars can either be towel dried or air dried.
Place the empty canning jars, opening side up, on the rack in a boiling-water canner.
Fill the canner with enough hot water to submerge the canning jar, plus one inch.
Boil the jars for 10 minutes for elevations of 1,000 feet or lower. For higher elevations, add 1 minute to the boiling time per every 1,000 feet of elevation.
Remove the jars from the canner, and slowly drain the water.