I have done a search but can't find exactly what I am looking for - so - can anyone advise me on doing a quick, not to terribly intrusive CLA on a Betax #4? I have been told that one can pretty safely clean shutters that may not be running correctly, with Ronson lighter fluid. If so, would I remove the front cover (4 screws) to get at the movements that need to have the fluid applied? Any tips? Shutter is working but 1/2 sec seems closer to 1 sec, and at times seems to hang open for longer.