Wherever you put your sunglasses, make sure the front face up to prevent any scratching. And you'd better put them in a hard case before you put them in a handbag, so as to avoid being damaged by keys, combs, copper and other small objects.
The way you maintain your sunglasses is the same way to take care of your eyeglasses. Regular cleaning, storage, storage should be developed into daily habits, if there is stain on the lenses of your sunglasses, don't remove it with your nail, it will scratch the surface easily.
If the frame or lenses are contaminated with dust, sweat, grease, etc., please use neutral detergent warm water cleaning, and then use a soft cloth to dry, you should not put them soak in water or expose to the sun for a long time.