1. The citrus peels that are usually eaten intermittently are dried, and collected into a certain amount and soaked in a basin for three days and three nights. The water is changed every day, and the water must be squeezed dry when changing the water.
2. Squeeze the soaked orange peel dry, cut into strips, put in a casserole, add water and boil. Cook for a few minutes, turn off the heat, pour out the water, let cool and squeeze dry.
3. Add plum sauce, salt and water, bring to a boil over high heat, change to low heat, and boil until the orange peel is soft.
4. Add rock sugar, continue to simmer on low heat, and stir constantly with a spoon to prevent the bottom from getting muddy. Turn off the heat and let cool when the soup thickens.
5. Put the tangerine peels cool and put them in a bottle and store them in the refrigerator. The bottle must be cleaned and dried with kitchen paper.
