Hm, I've used WD-40 on everything from 115 VAC power switches to VHF
slug-tuned inductors, potentiometers, and relay contacts. Whatever
conductivity it might have, hasn't been a problem for me. I wouldn't use
it on 100 meg level impedances, but more from worry that it would pick
up dirt and grunge.

What sort of experiment can you suggest that will demonstrate and
perhaps allow measurement of its conductivity?

Roy Lewallen, W7EL

Dan/W4NTI wrote:
WD-40 is somewhat conductive. So be careful of it around insulated parts.

Dan/W4NTI