Use citrus fruit with as thin peel as possible and do not make a larger portion than you can use up in a reasonable amount of time. Store the marmalade in the refrigerator.
sugar to taste
 Wash the citrus fruits well. Cut off the tops and bottoms and cut the rest into four wedges. Remove as many pits as possible from the wedges.
 Run the fruit wedges through a meat grinder or in food proccessor (pulse until fruit and skin are mashed).
 Stir in sugar and preservative, follow the instructions on the package.
 Spoon the marmalade into clean glasses and screw the lids on tight.