A simple but seeming absurd explanation of LEC is salty gas. That is the gas phase contains a small amount of electrolyte. Then, to made a electric cell one could use redox potential as suggested by Alan.
I made a brief test on this (it actually was for testing effect of high humidity): I wetted a bit the WE with water first, and then with diluted HCl. Result: no effect on the "dead" LEC, it didn't resurrected (no voltage, no current). Apart from this, Frank also made some test at -55°C, to exclude the effect of humidity.