Bring a quart of water to boil. Boil the lids for 3 minutes turn off heat and let rest. If you have a keep warm setting on your stove, add jars to a pan and set in oven till needed. If not turn oven on to 150Fahrenheit. Wash the plums, poke 2 holes with a knife on both sides. Now add to a pot and just cover with water. Boil for 30 minutes.
Reserve 4 cups water used for boiling plums. Add lemon juice and sugar and simmer until sugar is dissolved. Bring to a boil. Put the warm jars in a bowl with paper towels in bottom. Add the plums into the jars. Really press them in. Add salt a teaspoon of salt per pint jar. 2 teaspoons salt to a quart jar. Same with the lemon juice.
Add the syrup to about 1/2 inch from the top of rim. Add the lids make sure to wipe the rims before adding. Place in a canning pot with a rack in bottom. Process for 30 minutes keeping water 1-2 inches above the tallest jar. Let cool on a towel away from drafts for 24 hours. I covered mine with a kitchen towel. Check the lids to make sure the sealed before storing. I hope you enjoy!!!
