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Sanitize the canning jars and lids in boiling water. Dry well with paper towels. If you have a dishwasher, you can clean the jars in the dishwasher instead of using boiling water. You'll still need to boil the lids, however. To reduce the amount of wait time, it's best to perform this step while simultaneously soaking or cooking the relish. Fill a water canner halfway with water. Cover it with its lid, and start heating it over medium-high heat. Allow the water to reach a rolling boil. It's best to prepare this water bath while the relish cooks. If you don't have a water canner, you can use a large stockpot with a heat-proof rack placed in the bottom. Note that a water bath is only necessary if you plan on processing the cans of relish for long-term storage. If you intend to use the relish within one month, you can skip this part. Ladle the finished relish into the sanitized jars, leaving 1/4 to 1/2 inch (0.6 to 1.25 cm) of empty headspace in each jar. Briefly and gently stir the sides of each jar to release as many air bubbles as possible. Use a damp cloth to wipe excess liquid from the jar rims, then tightly screw the lids on top of the jars. Carefully lower the cans of relish into the boiling water. Allow the water to reach a boil again, then cover the canner and process the relish for 10 minutes. Do not allow the jars to touch each other or the sides of the canner. The hot water should cover the jars by at least 1 or 2 inches (2.5 or 5 cm). If you live at higher altitudes, you may need to process the jars longer. For altitudes between 1000 and 6000 feet (0.3 and 1.8 km), process the jars for 15 minutes. For altitudes above 6000 feet (1.8 km), process the jars for 20 minutes. After you finish processing the jars, use jar tongs to remove them from the hot water. Cool them on a wire rack or folded towel for an hour, or until they drop to room temperature. After the jars cool, press on the center of each lid. If the lids stay down when pressed, the jars processed correctly. If it pops up, the jars are not sealed. Do not re-process unsealed jars; simply store them as you would store opened jars. Place the jars of processed, sealed relish in a cool, dark place. They should remain good for at least 6 months, but most will last for 12 to 18 months. Once you open the jars, keep them in your refrigerator and use the relish within one month. If you chose not to process the jars at all, you should still be able to store them in your refrigerator for up to one month.
Prepare the jars. Prepare a water bath. Pack the relish into the jars. Process the jars for 10 minutes. Remove the jars. Store sealed jars up to one year. Store open jars up to one month.