Rinse and remove stems from plums.

Cut plums in half and remove the pits. Discard the pits and add pitted plums in a bowl.

Chop up pitted plums and add to a pot.

Add 4 cups of water and bring to a boil. Boil for 30 minutes. Use a potato masher to help break up the mixture even more.

Put a colander or strainer over a larger bowl and cover with several layers of cheese cloths.

Pour plum mixture over cheese cloth and let the juice strain into the bowl. This can take up to a few hours.

Pour 5 1/2 cups of plum juice into a large pot. If you didn't get 5 1/2 cups of juice add in some water to make a total of 51/2 cups of liquid.

Add in 1 box of pectin and stir well.

Bring mixture to a boil.

Add in 7 cups of sugar and bring to a rolling boil. Boil for 1 minute, stirring constantly.

Remove from heat and skim off any foam.

Ladle into hot sterilized jars making sure to leave 1/4 inch head space. Add lids and rings and process in a hot water bath canner for 5-10 minutes.