1. Don't rub the inside lens using one's fingers, a towel or even lick the inside of the eye cup lens with their tongue. 2. Rinse them in cold fresh water after use 3. Lay them flat to dry your goggles.
Before you start to swim, you can dip your googles under the water to prevent them fogging up. To take good care of your goggles, you shouldn't rub the inside of your lenses, or they will be scratched and then affect your eyes to focus.