"Dirty" Volume on Carver Amp

Go to radio shack and get some potentiometer cleaner /lubricant spray. Open the amp (turned off of course) and spray the smallest amount you can into any opening in the potentiometer case while twisting it back and forth. That should fix it for you. If the problem persists you may need to replace the pot.

ProGold from Craig Lab is superb+ sound will be much better.

I would hit it with Caig DeOxit following instructions, and then follow up with CAI Lube. CAI lube may have been replaced with a newer name. It is for moving parts like pots. I think ProGold is for plated surfaces. See Caig for applications.