<p>I have found if your good at tearing down one of these and have the patients to do so, flood the lens barrel with lighter fluid with at least 5 drops of fluid. Install the fluid through the self timer slot. Let stand for a minute or so and do it again four more times. Let sit for an hour with the lens facing down. Do the same again and let stand for an hour on the film door back with the lens facing up. This way you can remove the inner and outer lenses without any problem for the seals are freed up from the fluid. Then you can soak the shutter and aperture leaves well by flushing more fluid through them I have personally let the shutter sit in a coffee can full of solvent for a week the stand out to dry out for a week I have some 15 years old still working fine since this has been performed by myself. No oiling is needed too. If you have the time to do this you'll be happy with the results</p>