[ossiblue]

What you describe is very common. Moist air enters the gauges from the trunk and condenses on the inside of the glass. Short of completely sealing the points of entry on the gauges or making the air inside the trunk moisture free, I know of no solution. If you have moisture droplets inside the glass, you might be able to get rid of it by removing the gauge and blowing warm air through the holes for the gauge lights.

I'm sure others have creative solutions, so let them reply.