How do you "fix" a NiCd battery that won't charge?
I've seen youtube videos of people using Arc Welders to "juice" an old battery that previously wouldn't hold a charge. Of course I know this is dangerous, and could result in explosion or fire. I have heard that there is a way to do this that doesn't involve a welder - maybe a car battery or a dry cell or something (still dangerous, I know). Has anyone ever done anything like this? How? How did it work?