TIP! Following manufacturing, silicone naturally spreads and leaves residue on the mask glass causing condensation while diving.
This phenomenon is particularly noticeable on rimless masks where the skirt is moulded directly onto the glass. Don't worry, though: it's totally normal for this to happen and there are simple and efficient remedies.
For this kind of problem we recommend using McNett Sea Buff & Sea Drops. These products are specifically designed for diving masks' cleaning and preparation and are sold by the majority of retailers.