Dirt, rust, mildew even asbestos - it's got it all
I was able to repair the volume control by using a little shim to bridge the break.
When I first tested the 71A tube, it tested very good. A few days later it was totally dead. I was getting set to toss it and start shopping for a replacement when it occurred to me to try touching up the pin contacts.
So I carefully unsoldered the base pins, removed the already loose base, tinned the wires, reattached the base and soldered the pins. Sure enough, the tube came back to life
I then dug into my box of dead tubes and resurrected more tubes including some blue Arcturus and a UX280
