Email, Messaging, & Video Calls Email Automatically Remove Old Mail From Mac OS X Mail Trash Get rid of old messages—and retrieve any that you want back 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 on September 11, 2020 Email Yahoo! Mail Gmail Tweet Share Email The Trash folder in Mac OS X Mail serves a few different functions. Among them is acting as an in-between holding spot for messages you want to delete. To save space, you can set Mail up to automatically "take out the trash" permanently after a period of time you designate. The instructions here apply to Apple Mail installed as part of Mac OS X. The steps are similar in other versions of Apple Mail, however. Here's how: Select Mail > Preferences from the Mail menu. Go to the Accounts category. Highlight the account with the Trash folder you want to configure. Go to the Mailboxes Behaviors tab. Under Erase deleted messages, choose the appropriate option (for example, One month/week/day old ). Close the dialog to save your changes. Mail that is of the specified age will automatically be erased on an ongoing basis.