Is it possible for the backside of the glass to get dirty? I've cleaned the front of my Panasonic CT-30WX54 to no end and I'm sure it's clean, but I swear the backside is dirty. Can really see it against a white backround.
I thought that was a sealed enviroment. Or, is the front glass actually separate from the tube glass with a gap in between?
I think there is an air gap within, at least that's how it looks on my CT-34WX50 with a flashlight up close and the TV off. But there may also be an anti-glare film on the outside of the glass which I suppose is possible that the adhesive can go funky like seen on old tinted car windows, etc. Try the flashlight method with the light at different angles.