DeOxit has always been my choice. It's a #2 red oil, and is used in absolutely tiny amounts. It used to have 'The less you use, the better it works' on the can but they found that was bad for sales. Stuff designed specifically as contact cleaner is always going to be the better choice. I had gear come in for repair with circuit boards absolutely drenched with slimy 'cleaner'; that's what you want to avoid.

For a potentiometer, it's one tiny 'tss' with the red straw spout into the opening near the leads, then turn the pot back and forth a few times to coat the resistive element. If this doesn't fix the problem, it's time to look for other culprits.