The initial stage of glass disease occurs when moisture causes alkali to be leached out of the glass. This becomes apparent when hygroscopic alkali deposits on the glass give it a cloudy or hazy appearance.  
This may occur within as little as five to 10 years of the glass's manufacturing. 
The glass may feel slippery or slimy  
and tiny droplets, or weeping, may be seen in high humidity (above 55%). 
The hydrated alkali can form fine crystals on the surface of the glass in low relative humidity (below 40%).
At this stage, it may be possible to gently wash the glass and remove the surface alkali.
This will help to stabilize the glass by reducing the surface pH, and by removing dust, soiling, and hygroscopic components that attract further moisture.