I've kept a bunch of those style caps from S-6 chord organs. My understanding is that those white and brown ones last forever and my cheap esr meter confirms that. I'm kind of nutty, but I strip those boards down and save the tag strips, wire and tube sockets. I reuse the wood for cabinets and the sheet metal for chassis.
I had/have some organ pulls like that. Man those organs have hundreds in them! Mostly I look for vintage yellow Astron's or blue Mallory's. I have found a couple Bumblebee caps too.
Generally though, I dont use used caps.