1 Rinse screw-cap jars in the desired size (for a total of 1150 ml) (approximately 39 ounces total capacity) together with matching lids in boiling water and leave upside down to drain on a kitchen towel. Rinse 1 lemon and 1 grapefruit in hot water, wipe dry and strip peels very thin with a vegetable peeler. Cut the peels crosswise into very thin strips (julienne).
2 Remove all the white skin from the peeled fruits. Peel 3 more lemons and the rest of the grapefruit to remove all of the white skin.
3 Cut out the fruit fillets between the separating skins and cut into pieces.
4 Cut remaining 3 lemons and oranges in half and squeeze. Mix with fruit fillets and strips of peel.
5 Weigh in total, 750 grams (approximately 26 ounces) of fruit pulp and mix with the jam sugar in a large pot. Bring to a boil over high heat.
6 Rinse figs and cut in half. Scoop out flesh with a teaspoon and cut into small pieces.
7 Weigh 150 grams (approximately 5 1/4 ounces) figs and add to the boiling fruit pulp. Boil until bubbly over high heat while stirring, about 3 minutes.
8 Skim the mixture with a slotted spoon and immediately pour into prepared jars. Close jars, turn over, and let stand for 5 minutes upside down. Turn jars over again and allow to cool. (Jelly stores well sealed and refrigerated for about 6 months.)
Tip: To preserve the jelly for longer, you will need to process the jars according to manufacturer's instructions, or visit http://nchfp.uga.edu/.