How to pickle watermelon rind
Pickled watermelon rind is made by peeling most of the green skin off the white rind that usually gets left behind once the red flesh has been devoured.
First, the white rind is cut into small chunks or wedges, then soaked in salt or lime water for as long as overnight. Next, it's drained and added to a pot of fresh water, where it is simmered gently until tender. (Boil your watermelon rind too hard and it will end up rubbery.)
At this point, the rind is drained and may be soaked again in vinegared water or added to a syrup that's been made by boiling together vinegar, water, sugar and spices like cinnamon, cloves and allspice. After allowing the rind to steep, this mixture is cooked for a few hours until the syrup is thick, at which point the watermelon pickles can be cooled and transfered to sterile jars.