You will need:
1 "D" battery dead is fine make sure its alkyline
Distilled water
000 or 0000 steel wool
Phosphoric acid (prep and etch by Klean-strip)
Stainless steel container big enough to put your parts in
Thermometer
measuring cup
heat source
Step one:
Take apart your battery apart and get the black stuff out only the black stuff (magnesium phosphate i think it is) throw away the silver looking crap. put the black stuff in a bag and crush it into a powder.
Step two:
Pour 1 gallon of water into your container and bring it to 180 to 190 degrees F.
Step three:
Add the contents of 1 battery (only the black stuff)
Step four:
Add 1 pad of steel wool that has been de greased, and add 1/3 to 1/2 a cup of acid.
Step five:
After steel wool is disolved you are ready to park.