I have seen it countless times; a diver with a new mask so fogged you can’t even see his eyes – even after repeated applications of a defog solution! This can be extremely frustrating and even dangerous. What is happening here with new masks is that during the manufacturing process a thin film of silicone accumulates on the mask lens. This silicone is resistant to any of the conventional de-fogging measures. The solution is to “pre-treat” or “prep” the mask by removing this film prior to its use.
1. To remove the film, use a slightly abrasive agent like toothpaste. Avoid gel type toothpaste and go for common white toothpaste. NOTE: THIS IS FOR GLASS LENSES ONLY, NOT PLASTIC (POLYCARBONATE) LENSES. Plastic lens masks, such as the freediving favorite AquaSphere Sphera mask, scratch easily and may even come with an anti-fog agent already applied to the lens. Toothpaste, or other abrasive agents, as well as fingernails may scratch and ruin plastic lenses! If you decide to pre-treat your plastic (polycarbonate) lens with toothpaste, do so at your own risk. One way to minimize scratching plastic (polycarbonate) lenses is to use a soft, wet washcloth and rub lightly in a circular motion.
2. Take a thimble-sized amount of toothpaste and rub it on both sides of the DRY lenses. Give it a good circular rubbing with your CLEAN fingers.
3. Rinse the lens while rubbing away the toothpaste. Note that toothpaste may accumulate in the edges, so use a little more water pressure if needed to remove it, or you may use a soft, wet washcloth.
4. Once the toothpaste is rinsed away, DRY the lens with a clean towel or rag.
5. Repeat these steps, drying the lens in between each application, 5 to 7 times.
Watch the very detailed and very informational two-part video series:
A couple items for you to note: Some instructors say not to use mint toothpaste as it will sting the eyes. This may be true, but a very thorough rinsing after each application should be fine.
A note on SoftScrub®: Also, many instructors say to use an abrasive cleanser like SoftScrub® to remove the film. SoftScrub® claims it is safe to use on glass but I am not a fan of abrasive cleansers for treating a mask. They have several chemicals that may be harsh on the silicone skirt and harsh on the skin. And, if a mint flavoring can sting the eyes if a little is left in the edges, imagine a cleanser – that could really be problematic. If you decide to go with a SoftScrub® cleanser to pre-treat your mask, follow the method above and in the video, using a very sparing amount, rinsing and drying thoroughly. DO NOT use SoftScrub® products that contain BLEACH! And DO NOT use SoftScrub® on plastic (polycarbonate) lenses! Again, it is best to avoid the abrasive cleanser and go with plain ole toothpaste.
A note on Fire: Floating around in the cyber-expert world is a technique of using fire to burn off the residue coating on a lens. DO NOT DO THIS! There is no need for this procedure as there are simply too many things that can go wrong and could easily ruin your mask.
Be safe, gentle and conservative when pre-treating your mask. And use some good common sense – like no fire, nor bleach. Following these steps and the instructions in the videos should get your mask ready to go! Remember, that pre-treating the mask does not prevent it from fogging on every dive. You will still need to de-fog your mask properly before each and every dive. For more information on that, see my article How to Defog a Diving Mask.