Get the jars ready by heating them in hot water, and then fill the water bath canner to the halfway point with boiling water. Prepare a tested food preserving recipe, and fill the canning jars with the food mixture. Clean jar rims and threads using a damp cloth, seal jars and process according to the recipe's directions.
Make sure you use glass preserving jars and lids that are free from cracks, scratches, nicks and uneven or sharp edges. Fill a large pot halfway with water, place empty canning jars in the pot and heat to simmering temperature. Keep jars heated until ready to use, but leave jar lids and bands at room temperature. A jar funnel helps you pour jams, jellies and sauces into canning jars without spilling them, and an air bubble remover tool gets rid of trapped air. Place filled jars into the canner's rack and submerge into the water.
During the hot water bath processing stage, water inside the canner reaches a rolling boil. Don't remove canning jars immediately after processing. Instead, let jars cool for at least five minutes before removal. Place warm jars upright onto a towel, and don't disturb for 12 to 24 hours.