Here is a video on how to revitalize or restore batteries from throw aways to rechargeable batteries. http://www.youtube.com/watch?v=78tNoGFgPuk (http://www.youtube.com/watch?v=78tNoGFgPuk)
Maybe you know also that zinc carbon batteries could be produced as rechargeable with very very low cost added to actual process. There was a lost patent somewhere but it's obviously not used due to economic reasons. ;D