I use a spam filter called MailEssentials, which puts spam emails in a folder called "SPAM" in my users' mailboxes. I'd like a way to automatically delete the spam that's over 30 days old. Is that possible? I looked into using Powershell, but it seems to be only capable of deleting mail in a default folder like Inbox, or Deleted Items, unless I'm mistaken. Thanks!

As I understand it, the Retention Policy only works on built-in folders, and "managed folders".

Oh OK, thanks. I guess I should have mentioned I'm using Exchange 2007. But I'll be looking forward to upgrading now.