Peel peaches. To loosen skins, submerge peaches in boiling water for approximately 30-60 seconds, and then place in cold water for 20 seconds. Slip off skins and prepare slices 1/2-inch thick.
Place slices in water containing 1/2 tsp of ascorbic acid crystals or six 500-milligram vitamin C tablets in 1 gallon of water to prevent browning.
For fresh fruit, place 6 cups at a time in 1 gallon boiling water. Boil each batch 1 minute after the water returns to a boil. Drain but keep heated fruit in a covered bowl or pot.
Combine water, sugar, Clear Jel®, and, if desired, cinnamon and/or almond extract in a large kettle. Stir and cook over medium high heat until mixture thickens and begins to bubble.
Add lemon juice and boil sauce 1 minute more, stirring constantly. Fold in drained peach slices and continue to heat mixture for 3 minutes.
Fill hot jars without delay, leaving 1 1/2 inch headspace. (SB Recommended based on seepage issues) Remove air bubbles and adjust headspace if needed.
Wipe rims of jars with a dampened clean paper towel. Adjust lids and process immediately. Process in a water bath canner for 30 minutes.
Recipe from USDA Home canning