PREPARE FRUIT: Remove skins from fruit in quarters. Shave away as much of the white layer (the pith) as possible with a serrated spoon or sharp knife. Cut into very thin slices. Combine rinds with water and soda in a large saucepan. Bring to a boil and simmer, covered for 20 minutes. Stir occasionally. Chop peeled fruit, discard seeds. Add to cooked rind and continue simmering for 10 minutes. Measure 3 cups (750 ml) fruit mixture in a large saucepan. TO MAKE MARMALADE: To the 3 cups (750 ml) fruit add the sugar. Stir well. Heat on high and bring to a full rolling boil, stirring constantly. Boil for 1 minute. Remove from heat and stir in liquid pectin. Skim off foam. Stir and skim for a full 7 minutes. Ladle into hot sterilized jars and seal. Makes 5 1 cup (250 ml) jars. Calgary Co-op Advertising Flyer Jan. -0ºC eb. 3, 1991