Stop Mask Fogging!
Mask fogging is one of those problems that sounds harmless enough, but this small issue can ruin your whole snorkeling experience, and could even be dangerous. So what can be done about it?
First off, you should be sure that your equipment is clean, even if it is brand new. The reason is that there is usually invisible manufacturing residue on the lens of your mask that can cause issues with fogging if it not removed. The best way to clean it is to use soap, warm water, and a washcloth to buff off anything that may remain on lens. See also cleaning your equipment.
Ok, now even with a clean lens, fogging is still likely to occur, what can be done about it? The quick and dirty way is apply a film of your own saliva, yes, spit, on the inside of your lens. Your spit is sticky enough to remain on the inside of the lens long enough to prevent fog for a snorkeling session, but you may need to reapply as necessary.
Toothpaste, surprisingly, is another cheap trick. You’ll want to apply a small amount and rub it around on the inside of the lens with your finger or a cloth. Allow the it to sit for at least 30 minutes, then wipe out all the residue. This should leave an almost invisible film that will prevent fogging. It's not recommended to use this trick over and over again because the toothpaste will start to leave scratches on your lens.
Baby shampoo, baby oil, and dishwashing detergent can also do the trick. Other shampoos and soaps may work as well. With the soaps rub in a small amount, then lightly rinse. With the baby oil, you should just rub a light coating all inside with your finger, but don’t rinse or wipe afterwards. Be advised that if water gets into your mask and mixes with the soap or oil, it could irritate your eyes.
Now, the best solution for a foggy mask IS a product designed specifically for the task. There are many available and they all do the same thing and perform well. Before using one of these products you should definitely clean your mask thoroughly with warm soap and water, especially if you previously used one of the other improvised methods above. The instructions will vary, but you’ll either apply the product directly using a built-in applicator tip, or by using a cloth. There’s no need to use a lot, and you’ll want to conserve it since most anti-fog gels come in small, travel-size bottles.
Whichever method you end up using, be sure to keep in mind that the specialized anti-fog gels are going to be the best bet to preserve the longevity of your mask lens while increasing safety.