Faulty cable? Dirty contact?

I've recently been getting very brief (fraction of a second) dropouts in the left channel of my beloved AB1266 Phi TC headphones.  I'm hoping it is something simple like some sort of corrosion on a contact point where the cable plugs into the left ear cup..although considering the exhorbitant cost of that cable it should hardly be expected to corrode.  The dropout sometimes happens when the cable is moved on that side.

I hesitate to have to ship the cable and/or headphones to Abyss for repair if it isn't necessary.  Does anybody have a suggestion for a good effective cleaning solution or method to try first?