Issue with headphone socket/volume control

For a while now my Mpc Live 1 has had an issue whereby the left headphone channel crackles very noticeably when adjusting the master volume knob on the rear panel. Once the level is set it's fine, but it's annoying and will affect its resale value, which is looking to be a relavant issue for me.

Just wondered if anyone's had the same problem and if and how they were able to fix it?

Might help to wiggle it some more. It's probably dust.

Might need to spray some Deoxit into the knob... but I'm not sure how much of a project it is to take it apart to do that.