This is about chemicals. I had this somewhat old (10+ year old) Marshal JCM900 guitar combo amp that has been collecting dust in my studio. Not just literally, really.
And of course after such a long time of no usage, the potentiometers had squeaky sounds when I booted up the amplifier. I had a spray can of WD-40 back home, assumed that this miracle chemical would fix anything, but especially one of the volume knobs still didn’t work properly.
So today I stopped by one of the local Frys and looked at other solutions, I found Puretronics contact cleaner, it was a cheap can, $6, so I took one home. I sprayed the pots, and yes, now they work fine.
The local Starving Musician also sold me an old Marshall channel switcher, for $10, and of course this one didn’t work. So I sprayed it with Puretronics, and yes, now it works fine.
Lessons learned, keep a bottle of this around, there’s a lot of stuff in your studio that could get dust and dirt inside the volume potentiometers, sliders, contacts and so on. There could be many cases where you think your equipment is broken, while all it would take would be to fix bad connections with something like this.
The other lesson learned was that WD-40 is not that universal; use something dedicated for electrical contacts. No, Puretronics has not sponsored me. That bottle I purchased today should be enough for the next five years or more.