Things You'll Need
Mason jar lids
Mason jars are often used to can fruits, vegetables, soups, stews and condiments, and can be reused if the proper precautions are taken. Once Mason jars have been heated and sealed, harmful bacteria can not contaminate the food. If the jar's lids are not sterilized or replaced correctly, bacteria can taint the foods you want to preserve in the jars next. To prevent this from happening, Mason jars must be resealed correctly.
Fill a pot full of water, and place the used Mason jars and lids into the water. Make sure that you have previously washed all of the jars and lids using dish soap and water to remove any remaining food residue.
Heat the pot over high heat until the water boils. Boil the jars and lids for at least 20 minutes to kill any lingering bacteria.
Use canning tongs to remove the jars and lids. Set them onto a towel to dry.
Fill the jars with the food that you want to preserve.
Wipe off the rims of the jars with a towel to remove any spilled food.
Screw the sanitized lids back onto the jars.
Fill a canner 3/4 full of water.
Place the filled jars into the canner, making sure that the jars are upright and fuly submerged in the water.
Boil the jars for one hour, then remove the jars with the canning tongs. The lids of the jars will be resealed after this process.