Slice the cantaloupe in half. Scoop out the seeds and stringy fibers. Cut the halves into three or four slices each so that you end up with six to eight pieces of melon.
Peel, making sure to remove the thin green layer just under the skin. Rinse off any debris that might have brushed off onto the fruit from the peel. Cut each slice into mini-slices approximately ½ inch wide and 1 inch long.
Mix the cantaloupe pieces with sugar in a large bowl. Cover the bowl. Refrigerate overnight.
Mix in the lemon juice. Pour the fruit and sugar mixture into a pan. Bring it to a medium boil over medium heat, stirring constantly to keep the fruit from sticking to the bottom of the pan. Continue to cook and stir until the melon turns clear/translucent and the juice has thickened.
Pour the mixture into the jars. Fill the jars up to ½ inch from the rim. Wipe the rim and cap each with a lid and ring per the jar manufacturer’s directions.
Place the jars in a water bather and cover with hot water. Process for five minutes after the water has begun to boil. Remove from the water bather. Cool and store in a cool, dark place until you are ready to use.