Radio Shack used to carry "Tuner Control" cleaner and lubricant, but you probably won't find it there any more. But, just in case they haven't gone completely non-technical, the catalog number is 64-4315. I keep a can on the desk. You never know when you might need to clean a pot.
If the pots in your CH stick are spikey/jumpy, it probably is time to replace them. The way the stick is constructed makes it hard to get dirt or dust in them.