Battery recover & more
http://www.youtube.com/watch?v=_EVOE-ZxY7w
Detailed step by step conversion of a lead acid battery to lead salt. Alum (Aluminum Sulphate) is used in this video.
How to deal with maintenance free batteries.

This conversion generally results in at least a 1V drop in maximum battery voltage!
It changes the battery from shallow cycle to deep cycle.

In my tests I have used 1:10 Chemical to distilled water. That is, 100gm chemical to 1ltr (1Kg) warmed water. This works for Alum (Aluminum Sulphate), Sodium Sulphate (Gauber Salt) (this is close to saturation point at 0 deg Celsius) and Magnesium Sulphate (Epsom Salts).

Any conversion is made at your own risk! Please take safety precautions and dispose of sulphuric acid and any lead waste thoughtfully! (where it can't get into the food chain!)

Please check out Energenx for more detailed videos on Alum Batteries