Red to black wrote:
One of the old (almost retiring age then) engineers at my first job swore by using a drop of dirty/used engine oil from the dipstick of his car to clean/alleviate noisy volume pots etc.
, but I honestly could not say how effective it was, nor recommend it.
I often get problems on control systems with switch contacts that only carry small amounts of current.
Indeed I faced this problem out on site, on an ancient generator changeover system that had failed. The auxialiary contacts on one of the circuit breakers had gone high resistance preventing the control system from operating.
The customer was faced with a non-operational system and having to source a long obsolete part when I had a bright idea. I racked out the breaker, rigged up a mains supply and a 100W lead lamp, and connected these in series with the contacts in question.
After operating the breaker by hand a few times, the oxidation on the contacts had burnt through and no longer presented a high resistance. The changeover system then worked perfectly, and lasted until the system was upgraded.
I've used this technique on wirewound pots too, although on a smaller scale with a bench power supply and suitable limiting resistor.