There are a few things you can do to clean inside of ski goggles if they have been stored in a dirty or wet environment. First, dry the goggles by shaking them off and then place them in a clear plastic bag. Next, use a mild soap and water to clean the inside of the goggles. Be sure to use enough soap so that it does not damage the lenses. Finally, dry the goggles and store them in a cool place.