CRT problem

I have a 10 or12 inch green screen CRT off an HP 9845B I need to clean up. . It has been stored in a damp environment and the silicon rubber 'bonding' the protective glass screen to the front of the CRT proper has developed large mould spots in side itself for an inch or two around the outside edge of the screen. I guess I am looking for suggestions as to how to readily separate theses two glass items without scratching etc so I can clean and rebond them. I thought at first there was a cavity between the glass on the CRT face and the protective glass out front- just a seal of silicon rubber round the edge- but no such luck-- seems like the silicon rubber stuff covers the whole area of the tube face- so I need to chemically remove it or ?? Any ideas?? The 9845B is running OK- getting a partial memory test failure at boot up but I don't expect that will be too hard to sort. Anyway-- that's next week's problem! Dave Brown Christchurch, NZ