A question to ask. Any ideas of the storage temperature range during these 12 years?

If within acceptable temperature limits, I would reduce the primary AC voltage to just a small fraction of the AC voltage
and power on, maybe a fifth of the normal AC line voltage.

Leave the component on for an hour or so, and then up the
voltage to a quarter of the voltage for an hour. Gradually increase the voltage for several hours until full voltage is achieved. A finger on the capacitor to check for warmth during this process. If by some outside chance there is warmth on the capacitor, then substantially reduce the voltage and continue to let the capacitor "form".

I have capacitors sitting for more than 15 years that measure quite good. There is no leakage on top of the capacitors nor
at or around the terminals.

Extreme storage temperatures is your main enemy.

Hope this helps.

steve

I’ve been here, as a member, even before the 2009 forum update (that's the join date on the profile which got reset somehow in 2009).
Anyway ...

I would reply with an on-topic remark, but for some weird reason, many of my posts and threads have been disappearing from this forum.
I’ve emailed Jim Austin about the issue several times but we’re getting nowhere.
As some of you may recall, I posted a lengthy thread right here in Amplification “Power in Overpower “ a few days ago.
It’s gone. I do have existential proof — the page was in my iPhone cache and I saved it as a PDF.
Jim A has a copy, too. I’ll post a link to it soon.
But until Stereophile can get to the bottom of the magic act issue, I’m holding off on participating.

https://webcache.googleusercontent.com/search?q=cache:G1NoiUl9ou4J:https://www.stereophile.com/content/power-overpower&cd=12&hl=en&ct=clnk&gl=us