During the manufacturing process, a thin film of silicone will develop on the glass lens. This film of silicone will cause rapid fogging that is resistant to conventional anti-fog measures. It is important to remove this film of silicone from the lens prior to your first dive. To remove the film you will need to scrub the lens inside and out with a mild abrasive. A paste toothpaste is ideal but a liquid scrub will also work. Rub the cleanser into the lens with your fingers several times and then rinse clean thoroughly.
Mask fogging is a normal occurrence, even after the film of silicone has been removed. Normal fogging can be easily prevented with after market anti-fog agents or saliva. Rub onto the lens and then rinse. Your dive will now be fog free!
Some after after-market anti-fog agents contain formaldehyde, alcohol, or other substances that may damage the plastic materials used in your mask. If unsure, avoid prolonged exposure of the anti-fog agent with the plastic parts of your mask.