For this article which is a global introduction to lubricating a lens I've taken a widely used rangefinder lens. This one came from a Zorki-6 from 1961, an Industar 50. This lens comes in both silver and black. This is the silver version made in 1959.
A industar lens, the Zorki-6 camera and a partially disassembled lens. It is held together with these tiny screws. Remove them to remove the rings.
There are 3 of these screws on each ring. Here is a lens with its rings removed.
These long screw stop the lens, so that you can turn it out while working with it. Remove the left long screw.
There is also one on the back, leave it alone, take out the screw. And take out the lens unit from the mount part. Remember in which position it came out! Otherwise it takes some time to put back.
In fact this is the lens, without the rangefinderrings and its mount. No need to disassemble further. Clean off all the old yellowish grease. If there is no fungus, then just gently clean the front and back lens elements with either a special lenspen, cleaning cloth, cleaning foam or a special alcohol solution.
Dirty rings... time to clean. I've used a chrome cleaner.
Note the difference? Left is clean, right is not.
Be carefull with cleaning... there might be sharp edges inside the rings. They can easily cut open your finger, as seen here....
Clean rings, it might take a bit of time but now they are nice and shiny again.
This is the dirt that came off. And the bottomring, cleaned and ready to be regreased.
The old grease, yellowish. The grease I use. Use not too much, but not to little.
My chrome cleaner, it is actually used for car bumpers, but it works miracles on these old lenses. A Zorki-C and Zorki-6 next to eachother. The left one is cleaned by a pro, the right one is cleaned by me. Not bad...
Two types of Industar 50's LTM 39mm next to eachother. Left one cleaned by a pro (from the Ukraine) right one done by me. I overexposed a bit on purpose to see if there were still marks left. Well, a few, you can't get rid of all of them. But the result is excellent.