If you have heavy soil or grime caused by saltwater, dust, sunscreen, or other substances, a drop of mild dish soap with warm water should safely remove dirt and grime without scratching your lenses. If you spend a lot of time in or on the ocean, get in the habit of rinsing your glasses off periodically under the tap. It will extend the life of your lenses.
Never use tissues, paper towels, or paper-based products to clean your lenses. Instead, use the Kaenon micro-fiber cleaning bags and cloths for everyday cleaning of your lenses. Be sure to avoid any household cleaners that may contain ammonia or bleach.