I need to do two things:
1) Select any email with a subject line containing non-ASCII characters and delete it. I can do the second operation, but the only way I can think of to ask it to look for anything other than ASCII is to use a regexp of .*![A-Z|a-z|0-9|\!\@\# ... and so on, and I expect there's something more elegant than that. Alternatively, I hear that sendmail can block messages based on non-ASCII text in the headers (including Subject), but I haven't tracked down how yet. Sendmail might be preferable, as the main times I get a lot of non-ASCII subject lines are when the server load is so high spamassassin drops the ball, and adding procmail instructions to that stress might be unkind.
2) Within the message body, find and replace the character  with something ASCII -- a space or a carriage return would be fine. Something about the email encoding from Macs scatters those throughout messages, typically at the end of lines (but not always), and it gives Mutt conniption fits. Would
this Procmail recipe do the trick (with a little tweaking)?
Feel free to point anyone here if they can help out. Thanks for any assistance...