Green grapes help in lightening the scars that are caused due to acne. Vitamin C in grapes encourages the formation of scar tissues and ligaments and helps to repair the skin. Dust a bunch of green grapes with 1 tablespoon of alum and 1 tablespoon of salt. Keep them wrapped in a foil and bake them for quarter of an hour. Apply the juice of these grapes on your face, leave it on for 15 minutes and then rinse with warm water. This is sure to visibly lighten the scars.