Go to your local music store and get some rosin. Should be in small block. I shave off dust like particles and put on string. You might want to check the shaft for oil or anything that might make it slip. Could need retensioning with new dial spring. One other thing I just remenbered is clean the tuning shaft bearings of old greese, use tooth picks or whatever, lightly greese.
:
::This dial cord works a little of the way but tends to slip. Is there some kind of resin I could apply to the cord to give it more grip? Replacing the cord is going to be a major job.