I used to think my system stripped off the headers, too, until a kind
soul pointed out that elm (used in the system I was reading from, and a
popular mail program) simply doesn't show all the headers (although one
might think it did, since there were so many :-)
 
The cure was simple: while viewing the message, type an h and
miraculously there appear an absolute gazillion of additional header
lines,  including the personal address of the original sender (even on
moderated lists).
 
As for those reading museum-l via usenet, most newsreading programs have
different commands for replies to individuals and to the list: hit your
'help' command to look for them .  ('help' is usually either an h or a ?)
The different commands automagically pull the appropriate address from
the 'missing' headers.
 
--bayla   [log in to unmask] (ignore the delphi.com address if
you can, please)