My life, My work, Its always an Adventure

I've seen a loot of questions in different newsgroups about how to clean
SMTP queues from a spam attack.

The easiest way to do this is to use the Advanced Queuing
Administration Command Line Interface tool (aqadmcli.exe)

Run aqadmcli.exe from a command line with the following syntax to delete all messages from all queues:

setserver "Servername"
delmsg flags=all

Run aqadmcli.exe from a command line with the following syntax to delete all messages from a specific sender address:

setserver "Servername"
delmsg flags=sender,sender=sender@domain_name.com

You can download aqadmcli.exe from:
ftp://ftp.microsoft.com/pss/Tools/Exchange%20Support%20Tools/Aqadmcli/aqadmcli.exe