A simple way to remove scratches from sunglasses involves rubbing regular toothpaste on the lenses with a microfiber cloth, washing them, then rubbing them with a baking soda paste using a cotton ball. Finally, wash them again.
Rub the lenses with toothpaste
Use non-whitening toothpaste that is not abrasive. Check the label on the box or on the front of the tube to determine the type of toothpaste. Do not use gel toothpaste. Dab a pea-sized amount of toothpaste onto each lens, and rub in gentle, circular motions using a microfiber cleaning cloth.
Wash the lenses
Run warm water over the sunglasses to wash off the toothpaste. Dry the sunglasses with a dry microfiber cloth.
Rub the lenses with baking soda paste
In a small bowl, mix a quarter cup of baking soda with enough water to form a paste. Spread a liberal amount of paste onto each lens on the inside and the outside surfaces. Use a cotton ball to rub the lenses in gentle, circular motions.
Wash the lenses again
Wash the sunglasses with warm water. Dry the sunglasses, and check for any remaining scratches. Apply and rub the baking soda paste with the cotton ball again as necessary.