Russian 35mm Viewfinder clean

[john341]

My 35mm finder has somehow picked up dust specs inside the finder. Anyone familiar with getting inside one of these finders? Not sure where to start. Thanks

 

[xayraa33]

It depends on what era the Rostock finder was made but some of the earlier made ones the eye-piece has a serrated ring that can be unscrewed to get access to the inside to clean the lenses..on later ones it is glued in and hard to next to impossible to remove without damage to the plastic.