Batboard

I have 3 alert monitors that the volume pots are quite stiff to turn them. What would be good to use to free them up?

Me too, every few years, but I am storing them in the damp basement. I usually use WD-40 or Liquid Wrench where the shaft enters the bushing (after removing the knob) and then work the knob back and forth. They free up after a bit of fiddling.