When making your mask, the manufacturer sprays the mold for the mask skirt with what is known as a releasing agent. This helps prevent the skirt from tearing when removed from the mold.

The problem is, despite the manufacturer’s best efforts to prevent it, some of this chemical remains on the mask skirt and leaches on to the mask lens. Unless removed, this and other chemicals involved in the manufacturing process can prevent your mask defog from working.


This is why your Open Water Diver course materials talked about the importance of thoroughly cleaning your mask’s lens prior to use. What some divers don’t realize is not only the importance of this step, but how much effort they need to devote to it.

  • To start, you need the right cleaning agent. We Sell a Defog Mask scrub combo Set by 500PSI, which is HIGHLY recommended. 
  • Second, you need to follow the directions. If using a commercial cleaning agent read the directions and follow them precisely.
  • Third, you need to be willing to invest the time needed to do the job properly. Plan on spending anywhere from three to five minutes, and applying plenty of elbow grease.

Generally speaking, you will apply your cleaning agent to the inside of the mask lens and then scrub vigorously with your thumb before rinsing. You will most likely need to do this several times.



One of the ways you can tell you are doing a good job is that your thumb will make a squeaking noise as you move it back and forth over the surface of the lens. Another way you can check to see if your mask has been adequately cleaned is to put the mask to your face and exhale into it, without first applying defog. Your mask will fog slightly — but it should not instantly become impossible to see through.

As always Remember the Friendly Staff at the dive shop is always there for you should you have any questions in regards to your gear or courses purchased at the shop.

*Disclaimer: In General the dive shop Staff will avoid giving Gear specific advice on any gear not purchased at the dive shop as any advice might harm you or your gear.

**Information Derived from (