Tremoverb problem

I've got a bit of an issue with the mid control on the orange channel of my tremoverb combo. It is scratchy around the 12 o clock position so I can't set it at this level (the 'scratchiness' at the 12 o clock setting means that the mid control skips immediately from too low to too high...if that makes sense!!)

Any ideas on how I can fix this? Perhaps I need to clean the pot? If so any advice on this would be much appreciated! Thanks!

Clean it with Deoxit Gold.

Use it to clean all of your pots, jacks, switches, tube pins, tube sockets, etc about once a year. Spray it on the pot and rotate from off to full at least ten times. Allow to completely dry and do not spray to much. A little is all that is needed. It can be found sold in many places...

http://www.musiciansfriend.com/pro-audio/caig-deoxit-gold-g5-spray-contact-conditioner-5-oz.?cntry=us&source=3WWMWXGP&gclid=CjwKEAiAxfu1BRDF2cfnoPyB9jESJADF-MdJco8k8vdzGdwDFZ7v7bH0rtQiBFMIywYnBRcHOKClLhoCcA7w_wcB&kwid=productads-plaid^157459348602-sku^429168000000000@ADL4MF-adType^PLA-device^m-adid^93130364907