[Exim] Stopping deferred fail messages

I finally got sick of all the spam, so I enabled 2 RBLs and made a custom
system filter...works excellent. In order to try to and get myself off
lists, I use a 'fail' in the system msg filter to bounce the spam...however,
most of the addresses aren't valid so the bounce message itself bounces and
gets frozen.

I have a bunch of those sitting here frozen taking up space in the log when
the queue runs. I've looked through the docs/faq for a way to do a 1-time
try on fail messages, but haven't found it. Don't think a retry entry will
work here...

Suggestions? :)

-Sam