If you want to clear your mail queue, you can create a script named clearmailq.sh with the following:
Install the following script as a .sh on your server
#####Mail Queue Cleaner#####
#!/bin/bash
echo Clearing Mail Queue..
cd /var/spool/exim/input
rm -rf *
exit
NOTE : Save this, and chmod 755. Now, crontab this script to run, again, there are better ways of doing this!