Predicta Screen Cover Going Bad

[Indian Head]

Can anyone tell me if they have experienced this? I have several Predictas and one (a 21" Holiday) has a picture tube screen cover that appears to be deteriorating. It is very cloudy or foggy with a look like it is turning white instead of clear, to the point you can barely see through it. Furthermore, once removed, the inside of the cover smells terrible, something like either very good cheese or very old socks. Any ideas?

Thanks,
John