Facebook users can send personal messages to other Facebook members using the website's messaging system. Each time you send a message to another Facebook user, a copy of the message is stored in a separate section of your Facebook message inbox. You can review your sent message history or delete any unwanted sent messages through the Facebook messaging inbox.
Log in to your Facebook account and click the "Messages" icon at the top left corner of the page.
Click the "Sent" icon on the left side of the page to view your sent messages. Click on a message to view it.
Click the right arrow button to view older sent messages. Click to put a check mark next to any unwanted messages and click the "Delete" button to delete them.
Click the "Select All" link to select all the messages currently displayed on the screen. Click the "Undo" button to bring back messages that were just deleted.
Deleting a message from your sent folder does not remove it from the recipient's inbox.