Request for immediate delete option

We allow anonymous commenting at our site (http://theforvm.org) but the vast majority of anonymous comments are spam. I've already created a group of known registered users to bypass the spam filtering, so it would be great if I had the option (under General Options) to immediately delete spam instead of having to wait an hour for a cron run to delete it. I can deal with the valid anonymous commenters on a case by case basis, but we can get dozens of spam comments per hour.