Ever complain about having to buy a toy because it needed batteries and your too cheap to keep on buying batteries? Well your answer is to resurrect the life of that dead battery with the schematics from the Afroman. So if you remember what a resistors and diodes are and not afraid of losing a finger or two, continue on to charging up your dead batteries.
The world rejoice this coming Christmas and the big two battery making kingpins cries foul.
You can fully recharge a depleted 9v alkaline battery at 63mA overnight without problems. You can fully recharge a depleted alkaline AA battery all day without problems. I recharged both types of batteries twice, and I would expect them to easily take many more charges. If you care about safety more than I do, attach a multimeter to the batteries and monitor them so they never reach more than 110% of their rated voltage.