Cut the peel of an untreated orange in thin slices. Soak the slices in a bowl of salted water for 24 hours placing a weight so all peels are covered with water. Rinse repeatedly to remove the salt, weigh the drained peels and add the sugar. Place them in a non-stick pan with a small amount of water covering the peels. Cook at a low flame until the sugar melts. When the peels become transparent and the sugar has become syrupy, remove them from the flame and place them on a grid to strain the syrup. Let the peels cool and store them in a glass jar in the refrigerator.