Wash the oranges, lemons, and grapefruit.

Slice the citrus fruit into paper-thin strips.

Collect the seeds from the sliced fruit and place them in a cheesecloth bag.

Measure the sliced fruit.

For every cup of fruit, add 2 cups of water to a pot.

Add the cheesecloth bag containing the seeds to the pot for added flavor.

Let the mixture stand for 24 hours to allow the flavors to meld and the pectin to release.

Remove the cheesecloth bag containing the seeds from the pot.

Cook the fruit mixture over medium heat until the fruit is tender.

Let the cooked fruit mixture stand until it is cool.

Measure the cooled fruit mixture.

Add an equal amount of sugar to the cooled fruit mixture.

Cook the mixture over low heat, stirring frequently, until it reaches a thick, marmalade-like consistency.

Pour the hot marmalade into sterile jars immediately.

Seal the jars and let them cool completely to ensure proper preservation.