ok. this sounds sort of like an issue i had with a super old jvc stereo receiver i rebuilt. i had one channel that would just cut in and out randomly with static and if you messed with the balance by rotating it a lot of pushing it in, it would sometimes fix itself to some degree.

i am pretty sure its a bad pot. it could just need cleaning as you say or it could just need replacing. if you plan to replace it, you need to find the model (should be written on it somewhere) or even just the size and style of pot it is (i.e. 10K, 100K resistance etc and wether or not it is linear or logorithmic) if you know that and go to an electronics store and get the replacement. the best option would be to write down all the pots info that you can come up with and bring that to the electronics store and ask them if they have that specific one or one with the same specs.

to do a proper job of replacing it, you will need a soldering iron and a solder sucker and solder of course. have you soldered or removed solder before? if not, i can try to describe the process and/or find a site that shows you how.

as for cleaning, i am not sure as to the usual procedure for cleaning them. i tried to clean the pot on the receiver i had, but that didnt help so i know mine needs replacing.

anyway, hope some of this helps you out.

-Jace