Day 1. Pare watermelon rind removing the green and red cutting into 1/2 x 1-1/2 pieces. (make pieces uniform) Mix 1/2 cup salt with 2 quarts water and soak rind overnight at room temp.
Day 2. Drain and rinse well. Drain again. Cook rind in fresh water until just tender. Drain.
Combine vinegar, and spices and sugar. Boil for 5 minutes. Add rind and boil until rind is clear. Remove from heat and let stand overnight. (at room temp)
Day 3. Drain syrup and boil for 5 minutes. Pour over rind and let stand overnight. (at room temp)
Day 4. Repeat day 3 until syrup is desired consistency
Final Day. Bring rind and syrup to full boil. Remove from heat and pack into jars and seal.
I usually bottle on day 5. Some recipes call for adding 2 cups of water into the recipe at day 2 with the vinegar, sugar and spices. I personally think the syrup is too thin. But try both and see what you prefer. Most of all, enjoy! You can also find Pickled Watermelon rind in "from Amish and Mennonite Kitchens" by Phyllis Pellman Good and Rachel Thomas Pellman.
TO PUT UP: I put my jars into a roasting pan with boiling water. After putting watermelon in jars and sealing (lids heated) I turn the jars over for 5 minutes. Then turn right side up and you will hear the "pop" when they seal