mass comment delete MU?

I am wondering if anyone has done anything with MU that would allow the site admins to delete all unmoderated comments across the entire install of all blogs, and perhaps delete all unmoderated comments that are more than a month old.. I wonder how many comments are just sitting around in moderation on dozens of blogs that have not been logged into in a while..

I also wonder if any plugins would allow us to turn off comments on all blog posts and pages that are more than a month old –

I’m thinking of trying to make some space in my database, and free up some server resources from comments spammers that may not be dealt with by my blog users. Any suggestions?