[PLUG] Mailling bounces messages from non-existant addresses

[Rich Shepard]

I have a script that uses mail to send messages to my notification list
addresses.

Some addresses are folks who've change employers or retired and I removed
their addresses from the list. Yet, three of those no longer on the address
list produce bounces from the recipient's mail server because they're no
longer there.

I grep'd all files in the parent directory and cannot find those addresses
anywhere on my system.

What might cause messages to go to those missing addresses? Does 'mail' have
a cache that might include them?

TIA,

Rich