1Peel off the green part of the watermelon rind, and slice into 2 inch pieces. Soak the rind in a solution of 1 gallon water and 1/2 cup salt overnight.
Remove rind from the salt water, and place in a stockpot with clean water to cover. Bring to a boil over medium-high heat, and cook for about 30 minutes, or until the rind is tender. Drain.
In a large pot, combine the sugar, 8 cups water, and sliced lemons. Tie the cinnamon and cloves into a cheesecloth bag, and place in the pot. Bring the syrup to a boil, and boil for 5 minutes. Add the rinds, and cook until transparent. Remove spice bag. Stir in red food coloring, if using. Ladle preserves into hot sterile jars, and process to seal.