This is a pretty clever product, the Greenivative GMAG ($27.50), that will charge 6 AA batteries at a time by adding saltwater. This magic charger uses magnesium anodes, and saltwater, to create electricity… which in turn will charge AA batteries. You can charge the 6 AA batteries 15 times before the magic wears off.
GREENIVATIVE Magic Magnesium "“ Air Fuel Cell. This environmentally friendly, lightweight, high power density fuel cell has a broad range of applications that require a safe, portable and reliable power source. This AA battery charger is perfect for a variety of applications and charges any Nimh or Nicd rechargeable battery . GMAG will charge 6 AA batteries in two hours and has a charging capability equal to about 90 alkaline batteries for a fraction of their cost. Powered by magnesium anodes and salt water (seawater or table salt and tap water), GMAG is a power source that is perfectly suited for home emergencies, the outdoorsman or anywhere conventional power is not available.
Video of this saltwater powered battery charger after the break.