First make a note, or take a photo of how the inner part of the catch is positioned, open and closed, so that you can be sure of reassembling it correctly. Also note which side of the semi-circular chromed handle has a square edge at the bottom, and which has the rounded edge.
The only way to dismantle the catches is to extract the pivot-pin from the semi-circular handle. If you turn the catch to half-way between open and closed, the end of the pin you can see is the 'head'. On the Contax (not sure about the Kiev) you can see 3 'flutes' where the head is peened to make it a snug fit in the handle. You cannot turn the handle far enough to knock the pin out from the other side.
Turn the catch to the closed position, with the handle folded down. The head of the pin is towards the 'front' of the back. Make a tiny wedge (from a matchstick, for example) and wedge it between the handle and the surround near to, but not covering, the head of the pin. This is to maximise the clearance between the semi-circular handle and the chromed centre-piece at the side OPPOSITE the head of the pin. Press the blade of a craft knife into this clearance (grind it thinner if it is too thick) so that the edge digs into the pin as near as possible to the handle, and try to lever the pin out. Do this repeatedly, and if the pin is not unusually tight you should eventually see some movement. The amount you can move it is limited to perhaps 15 thousandths of an inch or so, before the head of the pin meets the surround, but you can then turn the catch to the half-way open position and continue by using the same tool and method on the exposed head of the pin until it is free.
The knife blade needs to be as sturdy as possible subject to the limitation of the clearance available. I used a Stanley knife with the blade ground down somewhat. I think in the US the knife might be called a box-cutter or utility knife.
Hope this makes sense - if not, let me know!
