[morzh]

So, I took Deoxit D, lifted the cardboard dust cover from the pot, and, having located some openings, sprayed a little of it in.
I tried to keep the pot upright, so the cleaner does not go to the pot section.
Within a couple of minutes I had good contact in closed position.
Then I dripped some F5 to the shaft, in hope it penetrates to the rheostat and worked it a bit.
Will let it dry first.