The Delco-Remy condensers from the 1960's and before used an actual piece of paper for an insulator between the foil layers which did not deteriorate nearly as badly as the gel coating that was used in later production. They lasted about three days past forever! About the only way to destroy one was to hit it with secondary voltage that would actually burn holes through the paper insulation.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!