[MadMax]

Current conducting surfaces on Deans connectors are gold plated. Vinegar won't do a damn thing against them. However, you could rust out the spring plate on the male connector with acid exposure, or most likely get a nice green patina on inside your copper wire strands soldered to the connector terminals.

In diagnosing connection problems, my first troubleshooting approach is to try to bypass the connection with an alligator clip that I've soldered together myself (some are crimped).

I doubt that your connector has failed. I would check for fatigue failure of conductors in your wires at your connector ends. As much as I like Deans connectors for their current capacity and compact form, they do little to strain relieve wires connected to them. You might have also lost the spring plate on your male connector end which would not provide reliable contact.