You can make plum jam or jelly. Here's the jam recipe:
Plum:Wash and pit. For every 5 cups of plums, add 3/4 cups of water and cook until soft. Add 3 cups of sugar and boil until done,stirring constantly. You can feel it starting to thicken. Pour into half-pint or pint jars and,leaving 1/4 inch headspace, seal. Process 5 minutes in a boiling-water canner.
Here's the jelly:
Plum:Wash and pit plums.Cook with just enough water to prevent scorching. Cook until soft and press through a jelly bag or cheesecloth. For every 5 1/2 cups of plum juice, add 1 package of pectin and 7 1/2 cups sugar.Cook until done(pectin directions on the box for minutes boiled),.Pour into half-pint or pint jars,leaving 1/4 inch headspace and seal.Process 5 minutes in a boiling-water canner.
Jelly's cost more to make, you need to buy cheesecloth for straining, pectin for setting up better and alot of sugar.