[Arran]

There is also a fellow of Y.T that posted a rebuttal to the idea that non electrolytic caps had a polarity, Dennis Carter is the guy's name. In any event he explains, and shows why the test employed is not really valid, and explains why they don't denote the outside foil anymore on the body of the cap. I myself haven't really noticed a difference, other then the fact that the original caps are all leaky, so it would be impossible to tell anyhow. I've noticed that in many old radios they didn't even observe which end of the cap was connected where, the end with the line is supposed to be connected to the terminal that is closer to ground potential, but they often ignored the line.
Regards
Arran