I just did it. The display on my little phone-answering machine was
blinking "BL", so I took out the 9-volt battery (Eveready "Super Heavy
Duty") and stuck it in my little ni-cad charger overnight. Took it out
the next day and put it in the answering machine, which has been happy
for several days now. We'll see how long it lasts.

So much for all those ridiculous dire warnings: your battery will
!*&%^#(! ***EXPLODE!!!*** if you try to recharge it. Don't Try This At
Home! Leave It To The Professionals!

Sometimes batteries will leak if you try to recharge them. No big deal:
I've cleaned battery ooze off my recharger more times than twice, and it
still works fine. I figure it's still worth it. I've kept the little
AAAs in my old remote alive for about 5 years now by recharging when
they get low.

And of course the thing to do is to use a gentle, low-current charger
like the one I have. If you try to use a big honking power supply like a
car battery charger, then you could have a 'sploded battery on your
hands (duh!).

--
Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral.

- Paulo Freire