A brand-new mask often has a thin layer of silicone left over from the manufacturing process, which causes fogging. To remove it, use a pre-cleaner like toothpaste or Gumption – just a small amount rubbed gently with your finger (not a brush). Rinse well and repeat 3–4 times. Never use a lighter, as it can damage the mask and void your warranty. Once cleaned, use anti-fog on a dry lens before each dive, and rinse your mask with fresh water after every use. Store it in a cool, shaded place to keep it in top condition.