problem with non-displayable characters

[victor@algebraic.org (Victor S. Miller)]

I'm not really sure if this is a gnus problem or an emacs problem.
I'm running no gnus 0.1 (although the same problem happened with
5.10.6)  with emacs 21.2.1.  I routinely receive mail whose sender
and/or subject contains extended characters.  When I'm using gnus at
work on an x-windows system, everything is ok.  These are displayed as
cyrillic, chinese, special accents, or whatever.  However, when I
access my work account from home, my terminal type is a vt100.
However, when I go into summary mode, all hell breaks loose.  The
extended characters are displayed as gibberish which in fact appear to
look like control characters to my terminal so the whole display is
screwed up.  Even more puzzlingly -- when I deleted (or marked as
read) such emails, the rest of my summary is still screwed up.  Even
after doing C-L, or even quitting gnus or emacs, when I come back to
the summary of the folder in question -- all sorts of gibberish
overlays the subject of some a particular email which has no extended
characters.

How can I tell gnus (or emacs in general) not to try to display
extended characters when my terminal type is a vt100?

Victor