The volume control wart pod on the cable of my old and longsuffering Lenovo headset had been dropping out the right channel for a while, eventually prompting me to discover it comes apart by simply pulling on the halves:
There being no way to get closer to the open-frame volume pot’s innards, I eased a drop of DeoxIT Red along its edge (upper in the photo), slipped another drop into what’s presumably the wiper opening in the knob, and ran it through enough cycles to spread the juice evenly.
Reassemble in reverse order and It Just Works™ again.
The Smell of Molten Projects in the Morning 
Gotta love those Zero Dollar Repairs!