1. In a kettle put the plums and 2 cups of water and boil until skin is tender, strain through jelly bag and measure 3 1/3 cups.
2. In a kettle add the juice with sugar and boil stirring constantly.
3. Take it off from heat and skim off foam.
4. Pour into sterilized hot jars to within 1/8" of jar top. Wipe jar rims and adjust lids.
5. In a pan with boiling water, bathe the jar for 5 minutes.
6. Use as condiments or store in sterilized jelly jars covered with paraffin.