I have a pile of old cables with every sort of connector from bnc to pl-259. Most of the rubber/plastic cables are very dirty and oily, and no matter how much I clean them, they still feel sticky. They leave black smears on anything I try to clean them off with. Are they decomposing or what? Many of the connectors are very oxidized. Some of them have spots of green and some of them are just very dirty. BNC connectors, both male and female have lots of small crevices that can't be reached even with a toothbrush. Should I soak them in white vinegar? What's the most effective, least labor intensive way to clean these things? I would prefer not to have to spend several hours cleaning test cables, but I don't want the dirt/oxidation to spread....

The cables may be soft-degrading, although I have never heard of that. You need to rough up and use Brasso and/or lacquer thinner. What is the physical consistency of the cables? Are they very soft already? Chances are the oil on them is damaging them and it needs to be removed. Lacquer thinner will do that well.

To clean the cables i agree with Nick. Another thing to use is brake cleaner. Not sure about the connectors
Stan Ski