I had/have plenty of ancient NiCd cells that grew green &#;mold&#; across the (+) end. Dremel with the brushy-thing cleans it nicely, &#;though sometimes whirrs away the heatshrink if you linger too long.
If you are looking for more details, kindly visit Godson Tech.
Try charging it, see if it holds a charge. If it starts at 0V, chances are it&#;s got internal whiskers shorting it. Charge up a big capacitor and zap it a few times. Pound it good, enough to spot-weld the wire to the tab. Should &#;blow the fuses&#; of those whiskers.
Then, once it reliably holds a partial charge, charge it up sloooowly, like C/20 to even C/50. Let it go. They can trickle-charge forever at lowlowlow currents without too much damage.
If you want to learn more, please visit our website rechargeable aa ni cd batteries.
Cycle each cell a few times, see if it, well, works. Then, you&#;ve resurrected them successfully if so. If they stay bricked, or start to charge but keep discharging at those low charging currents, toss &#;em.
Æons ago, I grabbed a bunch of power-drills with 12V NiCd cells for about the price of just what the sub-C cells would be worth. Left most of the cells in-place, only would scrounge what I needed (and got kewl motors/gears from the drill if I needed any). Probably still got a bunch of those drills/cells somewhere.
So&#; they don&#;t leak, do grow &#;mold&#; around the seal, do grow internal &#;whiskers&#; that can short &#;em out, stink like vinegar if you overcharge &#;em enough to vent, but they can otherwise take a pounding and not complain much if at all. You really gotta kill &#;em good to kill &#;em dead. Eg, reverse-charge them, do other nasty nasty things to them.
For more information, please visit exit sign wattage.