I have to disagree with you guys. I spent 10 years repairing organs and amps. WD40 works very well. If the pot (volume control) is sealed pry the little tabs back just enough so you can get the little red tube in between the cover and the pot. Spray a little in there and spin the knob back and forth about 10 times. Bend the tabs back best you can and you should be set to go. If the pot is not sealed just stick the tube in a give it a short spray, you don't have to drown it. The trick here is you must get any contact cleaner into the pot. Trying to spray it in from the outside will not work. Most likely you will have to take out the screws holding in the electronics and slide them out to do this.

Tom