Chuck Gould wrote:

:I'd be willing to try one out to see if I could tell any difference,
:but they're not suitable for use with iron fuel tanks.

:Like I have said, I'm not claiming that these things work- merely
:intrigued by the possiblity that they might and that there may be some
:scientific basis for a magnetic field affecting the electrons of the
:hyrodgen atom.

The moon is made of green cheese, Chuck. That's just as likely as
these things working. The allegedly scientific explanation makes as
much sense as pointing a wand at your engine, saying "Abra-Cadbra!"
and expecting your fuel usage to fall. Don't take my word for it,
though. See what the FTC has to say:
http://www.ftc.gov/bcp/conline/pubs/autos/gasave.htm

If they worked, you'd know it. They're a scam.