Dave Smith Instruments SYNTHESIZERS

Just about any potentiometer will get crackly (for audio) or jumpy (for data) if it's left unused for long periods of time.

If you really want to keep dust out, you need to cover your synth with plastic or metal - cloth won't keep enough dust out, and may produce fibers/dust of its own.

The Deoxit product folks talk about here can help, but most modern pots are "self-cleaning". Just turn them a bunch through their full range of motion, and see if that helps.