This is the procedure to use when one of your accounts has been compromised, a spammer has flooded your mail queue, and you want to entirely clear it out.
Sendmail:
Via SSH, run these commands:
find /var/spool/clientmqueue -type f -delete
find /var/spool/mqueue -type f -delete
Postfix:
Via SSH, run this command:
postsuper -d ALL
Exim:
Via SSH, run this command:
exim -bp |grep "<" |awk {'print $3'} |xargs exim -Mrm
QMail:
Stop the QMail service first. If QMail runs via xinetd (i.e. in the case of Plesk) you can skip this step.
Via SSH, run the following:
service qmail stop
for i in bounce info intd local mess remote todo; do
find /var/qmail/queue/$i -type f -exec rm {} \;
done
service qmail start
SmarterMail:
Login via RDP. Stop the SmarterMail service.
Rename the spool directory, i.e. C:\SmarterMail\Spool -> C:\SmarterMail\Spool.bak
Start the SmarterMail service. Delete the old spool directory at your convenience.
MailEnable:
Login via RDP. Stop the MailEnable Postoffice, MTA, and SMTP services.
Rename the Inbound and Outgoing queue directories, i.e.:
C:\Program Files (x86)\Mail Enable\Queues\SMTP\Inbound -> C:\Program Files (x86)\Mail Enable\Queues\SMTP\Inbound.bak
C:\Program Files (x86)\Mail Enable\Queues\SMTP\Outgoing -> C:\Program Files (x86)\Mail Enable\Queues\SMTP\Outgoing.bak
Re-create the Inbound and Outgoing directories. Under each, create a sub-directory called "Messages".
Start the above MailEnable services. Delete the old queue directories at your convenience.