I seem to remember a Tom Swift story in which you could fill your gas tank with water and drop in a silver pill and the water would would turn into gasoline. Tom was trying to keep the formula from falling into the wrong hands.
Oh... wait..
I do have some Tom Swift books, printed on acid paper, that I'm trying to conserve. They belonged to my dad when he was a kid. I read them. Now I'm trying to keep them from rotting away.
/johnny