[Mailman-Users] Manually marking users as bouncing/bad addresses?

[NOW Website Coordinator]

I'd like to come up with a way to deal with the users who are not being 
handled by the bounce processor besides just unsubscribing 
them.  Basically, I want to be able to give our membership department a 
list of bad email addresses, which I figure I can somehow get out of the 
bounce log.  If I just unsubscribed them, I have no record of whether they 
wanted to be unsubscribed (and maybe couldn't figure it out for themselves) 
or were a bad address.

But because so many messages bounce to me rather than get processed, I'd 
like to be able to mark them in a way that they then get deleted through 
the bounce processor.

I see the "nomail" field in the membership page.  Is there a way I can use 
this?  Or is there some other way I can queue people up to be bounced?

By the way, is there any log of people who change their email address?  I 
haven't found it.

Thanks.