[MlMt] Delete/change email address for auto-complete list? Or a warn list?

[Randall Gellens]

Someone I've exchanged a lot of email with was laid off from his 
company, so his long-time email will stop working immediately.  I'm 
concerned that I might accidentally send email at that address, either 
because it'll be in the auto-complete list, or because I'll do a 
reply-all to one of his emails, or to an email from a mutual associate 
who did one of these things.

(1) Is there a way to delete or modify the emails that get 
auto-populated?

(2) Is there a way to create a warn list of emails that don't work, and 
if MM ever finds one of these addresses in a composition address list, 
it should warn me?

--Randall