Rollei prism

[mlphillips illips)]

Greetings,

I've a Rollei prism for my twin lens cameras that is depositing a sort of
black powdery substance on the focus screen. The prism does not appear to
be desilvering, so I'd guess that this is some sort of coating in the
housing that is wearing off. I can always remove the prism and blow off the
screen, but this has become rather annoying. Can it be rectified?
Thanks.

M.Phillips



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