Mirror and Prism Degradation in old SLRS
My question is this: is it possible to re-silver old pentaprisms? I've seen people get good results re-silvering old mirrors, but that is a flat plane of glass. Further is the quality that is fine for a mirror good enough for a camera pentaprism?
I ask because I've noted degradation of prisms on several Edixas and Prakticas I have, which results in a hazy, hard to focus image. When a good prism was substituted the finder image became sharp again, so I know it is not a problem with the focus screen or eyepiece. I also have one Praktica which has acquired an odd greenish tint to the reflex mirror which causes a similar issue but also makes the viewfinder image much dimmer.
On a couple of the Edixas there appeared to be a fungus growing on the prisms:
These prisms all gave hazy viewfinder images.
So how about it? Can prisms be re-silvered? Is it worth the bother? (ie. will the quality be high enough for use in a camera?)
Thank you in advance for any useful insights.