WS-420 BT volume potentiometer repair?

Recently started getting cracks/pops while adjusting the main volume of my WS-420 BT, regardless of the source (main head unit, direct aux, direct Bluetooth). Does okay if it is left at one volume setting but worried about ill effects to the rest of the speakers with using it for adjustment. Obviously not ideal to leave at max volume and use iPhone as volume control or adjust all 3 zones whenever slowing down boat.

So far I've taken all the external housings off and tried cleaning the volume potentiometer with compressed air and electronic contact cleaner, and rapidly adjusting knob too many times to count but still getting enough cracks and pops to make me worry about my components. Unfortunately the potentiometer boxes look pretty damn sealed which is to be expected.

Word from Wetsounds is that it is most likely dirt or corrosion, and if I can't get it cleaned then it's an entire board swap. Just wondering if anyone has completely taken their EQ down to basic parts and if it's possible to maybe swap the main and mic potentiometers or something? Or should I just take this as an opportunity to move to the Exile zone controller?