In fact, sunglasses can block the sunlight, but can not prevent from pollution damage, so you should keep it carefully . 

Actually, the way to maintain sunglasses is same as maintaining general glasses, cleaning, folding, storage to fall into a habit. But sunglasses often take off and wear, it will be scratched accidentally, so there are some details to remind you: when sunglasses get stains, do not use nails to scratch,  the frame surface will easy to get scratches.

Many people put them on their head, collar or pocket, when not wearing sunglasses. At this time, you can not use your body with big moving to avoid breaking or smashing. Or someone will put in the handbag, I suggest you put in a hard glasses box first, then put in the handbag, avoid lens scratching by key, comb, copper and other small thing, or stained by lipstick and other cosmetics.

Wherever you keep your sunglasses, make sure the lenses should be facing up.

Frame maintain：

Keep sunglasses clean: Sweat or oil on your skin can corrode the metal parts of your sunglasses. Washing sunglasses every day will help sunglasses maintain.

Avoid sunlight: Put sunglasses under the sunlight for long time, will cause the frame easily colour fading due to the Photothermolysis.

Correct wiping: Dry with a cloth for glasses. Do not touch the lens with hard objects, do not wipe the lens with fingers, please wipe the lens with clean cloth, reduce lens scuffing.

Proper storage: Lenses should not be placed face down. If not in use, try to put the glasses in a case, when not wearing glasses, please use lens cloth to wrap the glasses, put them in the case to avoid damage.