Email, Messaging, & Video Calls Email Automatically Remove Old Mail From Mac OS X Mail Trash Share Pin Email Print Screen shot courtesy of Coyote Moon, Inc. Email Yahoo! Mail Gmail By Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated December 10, 2018 What if you delete a message you shouldn't have? The Mac OS X Mail Trash folder is a godsend. It lets you recover the message easily. Another positive aspect of the Trash in Mac OS X Mail is how it keeps itself to a reasonable size by eliminating very old messages automatically. Automatically Remove Old Mail from the Mac OS X Mail Trash To turn this feature on and have old mail automatically removed from the Mac OS X Mail Trash: Select Mail | Preferences... from the menu.Go to the Accounts category.Highlight the account whose Trash folder you want to configure.Go to the Special Mailboxes tab.Make sure Move deleted messages to a separate folder (POP accounts) or Move deleted messages to the Trash mailbox (IMAP accounts) is selected.Now make sure One month/week/day old is selected under Erase deleted messages when:.Close the dialog saving changes.