renew CH stick?

[Igo kyu]

I have a feeling that I've seen posts about this here before, but search didn't seem to find them, which may be me not understanding search.

I have a CH stick, the Flightstick, the cheapest one, but still not cheap. The potentiometers seem to be gone beyond use, at least for the elevators, though the mechanism is apparently sound. Is there a guide online somewhere to replacing these knackered pots? what brands or grades to use would be useful too.