Defrost chicken feet or wings. Bring a pot of water to the boil, put in ginger slices and green onion, place chicken feet in and boil for a while. Drain water and wipe dry.
Heat white vinegar, put in sugar and stir until sugar dissolves. Remove from pan and place in parge bowl. Pour in cold water.
When vinegar sauce is cooled, put in chicken feet or wings and let marinade for 4 hours. Serve as cold dish.