There are some methods for repairing these lenses . First you must know what type of lenses you have before attempting to repair.Methods for plastic and glass are different. If it is plastic lens,use a bit of liquid detergent to wash it under warm,running water.
Rub it around lightly and rinse away.Then dry it with a soft, lint-free cloth. And then apply a coating of non-abrasive white toothpaste to fill in the scratches.Rub the coating around the lens for several minutes.Finally wash the glasses in warm, running water again and dry tnem with soft, lint-free cloth. If it is glass lens, apply a dry cotton swab with white, non-abrasive toothpaste to rub lightly over the scrarch for twenty seconds.Then wipe off the toothpaste with a clean,dry microfiber cloth.Dampen the other side of the microfiber cloth and use it to wipe down the glass lens until the scratches are gone.
You may remove the coatings on your sunglasses. So your lenses can't block harmful UV rays for your eyes any more. If there are many deep scratches on your sunglass lenses, you can buy a pair of new sunglasses. Or if your sunglasses are very expensive, you can take them to the eyeglasses store where you bought them and ask the stuffs to remove the lenses for you. You can ask them to recoat your lenses it they can do that for you. But I heard that opticians often get new lenses coated. They won't coat your glasses if you have used them for a long time. I don't know why. By the way, you can ask the optician.
Dude, there are many home remedy to repair the scratched lenses. But methods for repairing plastic and glass lenses differ. So you must make sure to know what type of lenses you have before apply on them. If they are a pair of plastic lenses, you can wash them under warm, running water. And then apply a dot of dish detergent to each lens. You can rub them in a circular motion on the lenses gently. Then you can rinse the soap away and dry them with a microfiber cloth.
You can try a coating of scratch remover polish. If that doesn't work, you can use petroleum jelly, non-abrasive white toothpaste or furniture polish to help remove mild scratches. These products can fill in the scratches and make them less noticeable. But if you are not good at doing this, I suggest you to turn to a friend who is good at doing this or ask an optician for help. Good luck!