Excellent, I am glad you got it working. Cycling non-soldered connections/pots helps keep oxidation down, especially if it doesn't see movement often otherwise.

In extreme cases, there is a product called DeOxit D5 that works extremely well. I have redone some 20+ year old hardware recently and they now work like new. That stuff works on everything, even electrical receptacles.

Fine steel wool can also bring old cable connectors back to life, but only if the problem's due to oxidation.
 
The more common problem, though, is broken wires at the connector. Musical cables are typically made from stranded wire for flexibility, and over time individual strands can break, raising resistance at the connector and resulting in a lowered signal level (and/or hum).
 
When that happens the best solution - if you're handy with a soldering iron - is to chop off the connector a few inches back and install a new one. If you're not the DIY-type, buy new cables (best to replace both of them at the same time so they age equally together) with high-quality metal connectors and strain reliefs.
 
The best cables are gold-plated because gold does not oxidize. However, this is an unnecessary extra expense if the cables spend most of their time plugged into equipment. But if you play out live and move your gear a lot, gold-plated cables can prevent problems from occurring at the worst-possible place and times: on stage before or during a performance.