It's been a few years since I've had to mess about with a potentiometer. I can see a can of motorcycle chain wax in the image. I'm sure that it will do the job, but I think, in the long run, it will attract more dirt/dust than using a contact cleaner. Hope you manage to get it working.
That was just for the gear and the piston part! I used the slightly less agricultural wd40 and some IPA on the tracks! Hopefully done the job