Sure your new diving or snorkelling mask looks fine to put on and get into the water, but that just won't work out well. You need to properly prepare the dive mask first by thoroughly cleaning it.
During the manufacturing process, a thin film of silicone and mould release agents will develop on the glass lens and skirt of your new dive mask. This film will cause rapid fogging that is resistant to conventional anti-fog measures. It is important to remove this film from the lens prior to your first dive.
Mask fogging is a normal occurrence, even after the film of silicone and release agents has been removed. Normal fogging can be easily prevented with saliva, after market anti-fog agents, or baby shampoo. Rub onto the lens and then rinse. Your dive mask should now be fog free! If it's not, you'll need to go back and clean your diving mask with baby shampoo again as described above.
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.
Warning: Cigarette Lighter
Some really old school types say to burn the residue off of the mask inside lenses with a cigarette lighter. How you do this without damaging the mask we don't know. Some mask manufacturers specifically say not to do this. This method could also damage tints or special lens coatings on masks.
Don't breathe out of your nose! If you keep breathing out of your nose your mask will continue to fog up regardless of what we tell you to do below!
Masks should be treated with a defogging agent before every dive or snorkel. If treatment with a defogging agent does not prevent the mask from fogging, it is possible that some residue is left over from the manufacturing process, or that you didn't properly clean the mask after your last diving or snorkelling outing. If so, you'll need to repeat the cleaning process described above.
Regardless of the brand or type of defog there are basically only three ways to defog your mask:
Start with a clean mask – The mask lens needs to be very clean so fog doesn't form. (Have we mentioned that enough times already?) Every once in a while it doesn't hurt to also clean the outside of the mask lens. It won't help to prevent fogging but you'll see better if the lens is clean on both sides!
Commercial Defog Products — Surfactants like McNett Sea Gold, and McNett Sea Drops can be used. Both approaches work equally well but require different application methods so it's mostly a matter of personal preference.
Spit – While we should be trying to sell you the 'you beaut' commercial solutions, our preferred pre-dive anti-fog is spit. Spit on the inside of the mask and rub it around with your finger. Dunk the mask briefly in either fresh or sea water. The goal is to leave thin layer of saliva on the inside of the glass. Spitting does not work well if the mask dries out before diving or snorkelling, so use this technique immediately before entering the water.
Caution: Rinse Bucket – Under no circumstances should you spit in a diving/snorkelling mask and then rinse it in the rinse bucket of a dive boat! This is an almost certain way to spread viruses! The rinse bucket on a charter dive boat should be reserved exclusively for those using commercial defog, or the dive boat's preferred defog solutions. All it takes is one sick person spitting in a mask and briefly dunking it in the rinse bucket to contaminate the bucket. We avoid this by rinsing our masks in seawater (works fine), fresh water from the shower hose if there is one, or even bottled water as a last resort.
Baby Shampoo – Another do it yourself pre-dive solution is baby shampoo. Baby shampoo can be used just like commercial defogging solutions. Many divers carry a bottle of 50/50 watered-down baby shampoo with their dive gear. A few drops rubbed into the lens and then briefly rinsed out just before the dive will keep a mask from fogging. We know people who prefer to apply baby shampoo neat onto the inside of the mask lens when the mask is dry just before putting it away for storage. Then you just give it a quick rinse before you dive. Baby shampoo is preferable to standard shampoo, as it is generally hypo-allergenic, less irritating to eyes, and biodegradable. Baby shampoo usually smells good, too.
Still having problems keeping your mask unfogged? Then exhale through your mouth only. If you breathe out through your nose, warm moist air comes into contact with the colder mask lens. This results in fogging. We are all primarily nose breathers and some divers find not exhaling through their nose difficult. Often divers who complain about their mask always fogging up are nose breathing.
For a large range of Masks for all conditions visit the Masks section in the The Scuba Doctor Dive Shop. There you'll find a wide range of mask types, plus mask accessories.