We are often asked about how to prepare a new mask to help prevent it from fogging up during your dive. There are a number of techniques from the traditional tried and tested (the method we'll run through here) to the insane (flaming the mask lenses). It is also only half of the job, proper anti-fog treatment before every dive will contribute hugely to stopping your mask steaming up during the dive.
The whole problem arises from the manufacturing process during which a very thin layer of silicone builds up on the lenses. This layer is not removed or overcome by anti-fog solutions and has to be physically removed in order to prevent the mask repeatedly fogging over.
This technique is very simple but effective and uses toothpaste to safely remove the manufacturing residue from the lenses. It is important to avoid using the higher abrasion whitening or stain removal toothpastes as this could cause tiny scratches to form on the lenses, giving a haze effect, which defeats the object of the whole process. Instead stick with the standard white toothpaste.
Please also note this technique should not be used on plastic lenses (polycarbonate) or specially coated lenses (such as colour corrective lenses). Plastic lenses will scratch very easily and the abrasive action of the toothpaste may detrimentally affect the corrective coating.
1. Take the toothpaste and squeeze a pea sized amount onto your clean finger.
2. Using circular movements thoroughly rub the paste over the inside face of the dry lens / lenses.
3. Again, using circular movements with your finger rinse the paste off the lens / lenses. The paste has a tendency to collect in the corners and edges so use a soft wet cloth to get right into the corners to get the last of the paste off.
4. With the paste removed, dry the whole mask using a soft cloth.
5. You will need to repeat the process a few times to make sure all of the silicone residue is removed. When done remember to give the mask a thorough clean to remove all trace of the toothpaste just to prevent any remnants from affecting your eyes during use. Remember that this technique only removes that manufacturing layer which causes most of the fogging problems.
It it still recommended to treat your mask before every dive. Most divers are happy with the traditional saliva to effectively prevent fogging but there are a number of off the shelf solutions from pastes (Absolutely Clear) to pre treatments (Sea Buff)