5 1/2 c. prepared plum juice
7 1/2 c. sugar
1 box fruit pectin

To prepare plum juice; wash plums, cover with cold water and boil until plums are soft and skins pop. Press through jelly bag, strain and measure. (At this point, juice may be frozen for later use.)

To prepare jelly: Mix the plum juice with pectin and bring to a boil, stirring constantly. Add sugar. Continue stirring and boil hard for one minute. Pour in sterile jars. Let set for one minute and skim off top. Seal with new lids. Let jelly cool slowly as sudden temperature change can cause jar to explode.