Auto-cleaning folders will help prevent your email quota being depleted by spam or deleted messages. When you log in to SmarterMail as postmaster/Domain Administrator you can set SmarterMail to automatically delete messages in the 'Deleted Items,' 'Junk E-mail' or 'Sent Items' folders.
Domain Settings > Filtering > Folder Auto-Clean
and select "Override auto-clean settings for this domain." Click the "Add Rule" tab to set when folders should be emptied.
Mailboxes can be cleaned based on the age of the messages or the size of the mailbox. Messages deleted during the auto-clean process cannot be retrieved, so be sure to allow enough time before auto-cleaning to review all of your messages.