as stated recently:
I think the combination you need are....
dilute sulfuric acid
galvanized steel (zinc + iron)
its a popular choice zinc/iron, readily available from 'scrap'
im using diluted acid from old car batterys and galvanized building scrap, works nicely....
now organizing a test engine
***ALWAYS REMEMBER to ADD:
ACID TO WATER ................AWWWWWWWW
NOT
WATER TO ACID.................WAAAAAAAAAAA
nice and easy to remember right
cheers
Adam