Steve and all,

  I've actually used a steam hose to clean - a salmon cannery in my case.  This method
did not significantly heat the surfaces being cleaned for any longer than the steam 
was directed at a particular part/area.  It was -very- important that we got any and all
fish left on the machines and floors and wood bins, etc. off to leave the cannery clean
enough for the next day's work.  It was cleaned once a day - after the crew went
home.
  I touched some of the surfaces after cleaning and they were, at most, warm.
  The pressure of the steam (force) seemed (to me) to be more important than
the heat.  And - the fact that using steam didn't leave a lot of water any where.

  I've heard many times that steam was one of the ways that stock cars were
cleaned and it makes sense to me.  I would also expect it to have been used
in reefers - but I may be wrong on that?

  I respect your research - but perhaps there are some 'missing items' that
have yet to be discovered?  Especially with respect to "era"?
  I just saw "A Few Good Men" (again).  In it they made a lot out of the
difference between what was "in the manuals" and what was actually
happening "in practice" ... oral history -can- be as accurate as what is
in the manuals/regulations.  There is no doubt in my mind about what
John Lewis and I did in the salmon cannery after the regular crew was
gone ... and I don't think there was a 'manual' for how to do the
cleaning of the salmon canning line ... *G*
                                                                                         - Jim B.
                                                                                                           - Jim B.