Cook cut up apples, with core and peel on, in enough water to prevent scorching. Add canned unsweetened plums. Put through a colander. For 8 cups of the apple plum pulp add 5 cups sugar and cook slowly 20 to 30 minutes. May add 2 teaspoons of cinnamon and some red food coloring last couple of minutes. Put in jars, seal and process 10 minutes in hot water bath.