"Not wanting to waste anything, this calls for the white part only of the rind. From Home Cooking."
piece fresh gingerroot
First, remove all green outer rind and red meat from watermelon rind and discard, retaining only the white part. Force remaining white rind through food chopper, using coarse blade. Measure it, there should be 6 cups. Put in a large saucepan or stockpot with water.
Cook slowly, uncovered, for 25 minutes, or until melon is translucent. Add sugar and lemon. Tie spices in a cheesecloth bag and add with salt to first mixture. Cook slowly, stirring frequently, for 1 hour, or until thickened. Remove spice bag, ladle mixture into hot sterilized jars; seal.