Howdy!
 
        Just a note on the acid types mentioned here.  James Max Peterson
was correct when he wrote "Phosphoric Acid is used in soft drinks to give
them a tart taste.  It will burn the skin if left on in concentrated form.
Hydrofluoric Acid will dissolve bone if left on the skin."
 
        I just wanted to point out that Hydrofluoric Acid, commonly referred
to as HF by those who use it, is extremely dangerous.  It is highly unlikely
that most folks will ever see it.  It is commonly used by the glass industry
to etch glass to reduce surface flaws that may induce stress points and to
frost glass, as it dissolves glass rather easily.  The reason that it is so
dangerous is that it can be quite deceptive.  It may not cause your skin to
have a burning sensation until well after you have been exposed to it.  You
may think that you got some water on you, at least for a while.    This
gives it time to start to go to work on your bone before you even realize
what has happened.  Once it gets into your system it reacts with calcium,
stealing it from every available source, specifically bone, muscle and even
neurons.  It is so powerful that a five square inch skin exposure is very
likely to be fatal.  Death is usually caused by heart failure as the calcium
required for muscle contraction (heart beat) is consumed by the HF.  Even if
death is not the end result, any exposure is likely to be a painful event.
After a time, depending on concentration (molarity) the burning will begin.
When it gets to the bone it will make you think that your bones are being
cracked open by a nutcracker.  That description was provided by a survivor
of an HF exposure!  You will get many injections of sodium gluconate around
the effected bone.  Morphine is usually required to control pain.  Seizures
will occur.  Muscle control and nerves in the exposure area are likely to be
irreparably damaged.
 
        Sorry to be so wordy but I want all to know the dangers of HF. Don't
use it!!  In the rare instance that someone does get a hold of a quantity of
HF, I want them to know enough so that they just don't use it.  We use it
where I work every day.  It is treated as the most dangerous stuff in the
plant.  It is!  A single pinhole in a rubber glove will ruin your life.
Please do not use Hydrofluoric Acid for anything.
 
Thanks for listening!