outside foil on unmarked PIO caps?

[Tsquared]

I scored a giant bag of NOS Pyramid paper in oil caps from a serious hoarder's estate sale.

They aren't marked as to the outer foil like a lot of older caps.  I read that if you hold the caps so you can read the writing on the cap, the outer foil should be on the right end of the cap... but I'm still not 100% sure this is accurate. Is this true for the Pyramids?

I did see a cool jig for testing for the outer foil connection on Youtube using just the input to a guitar amp, a toggle switch and a couple alligator clips.

Any help would be appreciated.

Tod

[FYL]

A large number of these old caps are leaky and thus unusable. They should be fully bench tested before any amp use.

Re. their orientation, check http://www.aikenamps.com/OutsideFoil.htm

[Shrapnel]

Gabriel had an easy tester any of us could build that can plug into just about any working amp.

Here's the youtube link to the device: http://www.youtube.com/watch?v=VP6ZIHXq6Yg

Here's the article on it on one of his sites. http://www.soundgaragetales.com/amp-building/outside-foil-capacitor