Make a battery using rusted iron and aluminium rods
Video at :
http://www.youtube.com/watch?v=aVyJQPJ2unY&feature=g-upl (http://www.youtube.com/watch?v=aVyJQPJ2unY&feature=g-upl)
Video is not very clear. If you observe closely, you will see a light stream of gas emerging from aluminium rod on right side.
Vineet.K.
Maybe you can get a round robbin effect using three electrodes.Iron,Al,nickle in one cell. Draw from iron-nickle redeposits onto al rod and draw from al-iron rechages the nickle. Depending how you pass what through which configuration.