Wash, drain, seed the cherries and run them through a meat grinder. Peel and grind or shred the pineapple. Mix pineapple with cherries using 1/4 as much pineapple as cherries. To the mixture add 2/3 as much sugar as there is fruit and juice. Cook this mixture until it is clear and thick, stirring to prevent burning. Pour hot marmalade into clean, hot Ball Jars. Seal immediately.
Source: The Ball Blue Book, 1930s