get some vitamin e capsules pierce them and squeeze out the oil onto the scar, massage in. The scar must be healed. x
If you have dark scars, natural remedies such as lemon juice, or tomato peel may work.... Or you may have to do an orange peel. You may want to look for products with salicylic in it, though make sure you get proper directions for use. What helped my marks lighten is isotrex and now I'm using dermafix products. It depends what scaring you have... So do some research on what may work best.
Bio oil really does work but it is expensive.