Most seasoned divers know that the best go-to method for keeping your mask clear is plain old saliva. Spitting in your mask may take some getting used to (it’s okay, every diver does it) but there’s no doubt that it works. But how? What’s the secret behind spit clearing your mask?
There’s no magic ingredient in your DNA. The reason spitting in your mask works is that the saliva acts as a surfactant. What this means is that your spit breaks the surface tension of other liquids, preventing water droplets from forming. Your mask fogs due to the temperature of the glass being lower than that of the air inside the mask. This difference in temperature causes condensation to build up on the inside of your mask and, next thing you know you’re looking through a blurry haze instead of a crisp, clear window.
Spitting into your mask and rubbing it around stops the droplets of moisture formed by condensation from clinging to and building up on the glass. Instead, the water beads and rolls away, allowing you to see clearly. This is why you may notice a small amount of water in your mask after you dive, despite having it well sealed to your face and not having had to clear your mask. That water is what would have fogged up your mask had the saliva or defogger not been there to break the surface tension of the condensation droplets.
Simple, no? If you’re still anti-spitting, never fear — there are plenty of other ways to prevent your mask from fogging!
Toothpaste
When you purchase a new mask, rub the inside with a plain, non-bleaching and non-abrasive toothpaste. Don’t use gel or the kind with microbeads; plain white paste works best. Rub a small amount around the inside of your mask with your finger, let it set overnight, then rinse well.
Fire
Yes, you can use fire to prevent fogging, provided you have glass lenses and not plastic. Run a flame along the inside of your mask lens, using a taper style candle or a lighter. Move the flame along the glass until it turns black, wait for it to cool, then wipe the soot away with a soft cloth. Repeat this process two to three times. Don’t let the glass get too hot, and keep the flame away from the silicone skirt.
Baby shampoo
Rub a few drops of baby shampoo on the interior of the lenses, then rinse. Why baby shampoo? Most are biodegradable so they won’t release chemicals into the water or your eyes.
Now that you know the secret of spit clearing your mask, give it a try. It’s simple, effective, and you don’t have to worry about forgetting to pack it in your dive bag.
