[Leica] Prism separation

[Douglas Barry]

I was upstairs looking for something and started going through some of 
my old cameras, and came across my Mamiya 645 1000S. Thought I might 
shoot a couple of tiring colour rolls over Christmas, but see that the 
prism in the viewfinder is showing signs of partial separation. It's not 
too bad, but has anybody got any suggestions as to how I could clean and 
reglue this?

Douglas