Autocompletion of addresses

[J]

Is there any way in addition to turning off auto complete on email to 
make it "forget" some of the addresses?
Somehow I sent mail to a wrong address and now it is self perpetuating 
in the list. I would like to wipe out all erroneously remembered 
addresses and thought I saw where to do this but can't find it now. 
Even if I have to start fresh with the list, I would like to do this.
Thanks