There are several function-based folders that have multiple commonly used names.  While SmarterMail may use Deleted Items, other mail applications use Deleted Messages, Trash, etc.  The same holds for Junk E-mail / Junk / Spam, and Sent Items / Sent Messages / Sent.  I would like to propose that the Auto-Clean mechanism provide a means of specifying folders other than Inbox, Sent Items, Deleted Items, and Junk E-mail as targets for Auto-Clean, with the folders simply being ignored if they don't exist for a given mailbox.

We typically encourage our users to configure their mail apps to use Deleted Items / Sent Items / Junk E-mail, but not all apps are configurable, and not all users take the time to do this.  Being able to specify these alternate folders as Auto-Clean targets would be very useful, especially the folders used for deleted items and junk email.