When you do have the exim queue on the server full of spam, so full that you cannot even open the email queue in your browser, delexim is a very handy script that will help you deleting the exim queue selectively, picking up only the bad guys and leaving untouched the legit email.

Anti spam appliance basically stop these nasty emails from reaching your inbox. It is a piece of software that identifies and isolates such email. It can be programmed in such a way that instead of inbox, all such emails are thrashed into a spam folder from where you can delete them after confirming they are spam.