🚀 go-pugleaf

I have revived a couple of Nicads myself.  basically you want to charge up
a capacitor (try samller ones at first -1 uF) up to over 100 volts with
a DC source.  An AC source (such as a wall socket) will work as long as 
the capacitor is NOT ELECTROLYTIC (I blew a few up myself - nice blue glow)
and the capacitor is rated WELL ABOVE 200 volts since you will cause a lot of 
current to flow - Come to think of it I DON"T RECOMMEND USING A WALL SOCKET!

CHarge up the capacitor using a transformer and rectified at around 150 volts.
Remove the capacitor (carefully - it could be a shoking experience if you touch 
the leads) and connect the diode "-" side to the Nicad "-" side and do the 
same with the "+" sides.  You might see a spark, but that's allright because
you want to spike the battery with an instant high current to break the
crystals which cause a battery to die.  The capacitor is necessary so
that the total amount of electrons flowing is instantaneous and then nothing.
I have noticed that is you have spiked a Nicad once or twice it should work
again - not quite up to new capacity but it will work.  Because the Nicad
already had grown crystals spiking the Nicad will revive the batter but
it is only a matter of time for the crystals to grow back causing the battery
to die again.

I hope this helped,  I can't be responsible for your getting shocked but
just be carefull not to touch anything high voltage - expecially the DC
from a transformer!