Reviving old hard drives

One of my other interests (yes, I don't just hack old computers!) is old cameras, still and cine (movie) ones. Anyway, a few weeks back I got a Bolex 8mm cine camera, one of the faults of which was that the focussing mount on the 13mm lens was jammed solid. And yes it was solid. I could not move it. Anyway, I took off all I could (aperture ring, focusing ring) and found the grease on the focussing mount had gone rock-hard. It was green in colour, and I could chip it off the metal parts with a screwdriver blade. Soaking it in propan-2-ol got it free enough to come apart with some force, whereupon I could chip off all the old grease. After regreasing it and putting it all back together (not forgetting to set the infinity focus point), it worked beautifully again. -tony