http://theezbatteryreconditioningreview.com/restauracion-de-baterias-pdf/

The process of restoring or reconditioning batteries that you considered to be dead is something anyone can do at home. Once you learn how to do it, you realize how simple the processes are. There are a couple ways to do this and it depends on the type of battery you are working on. About 95% of the rechargeable batteries can be restored.