OK, looking at Mouser's site as well as Taiwan Alpha's, these don't appear to be sealed pots. They should have SOME sort of opening to the resistor and wiper, according to what I'm seeing.
Get this first: https://www.sweetwater.com/store/detail/DeoxIT--caig-laboratories-d5s-6-caig-deoxit-contact-cleaner-5-percent-spray-5-oz And frankly, if you're doing any sort of electronic music work, you really should ALREADY HAVE this on hand, and the knowledge of how to use it.
But we're going to presume that you don't know how it works. So here's how to use DeOxit:
Put little aimer tube on the nozzle.
Aim tube into an opening in a pot that's being difficult.
Spritz a TINY BIT into the pot.
Exercise the pot for 15-20 seconds.
If there are still issues, repeat.
If you're using anything with analog controls, you will find yourself doing this A LOT. Learn how now! You're using equipment that, by its very nature, is prone to develop scratchy pots and the like, and if you don't know how to clean these, you'll either be doing a lot of scratchy-sounding stuff...or if you can't bring yourself to do this, then perhaps you should try building a synthesizer out of sticks, rocks, and other objects that don't require routine maintenance by the user.