Put prepared Plums in pot with water and bring to rolling boil

Boil for 20 minutes

Add sugar, lemon juice, butter and pectin

Bring to full rolling boil again stirring often

Boil for 1 minute at full rolling boil do spoon on ice test to make sure it will set if not boil longer

Put in sterilized 1/2 pint jelly jars and install lids and rings

Put in water bath canner and boil for 10 minutes in water

Take jars out of canner and let cool on counter test after cool to make sure jars sealed by pressing on tops of lids