How to Permanently Delete Private Messages in Facebook
Through Facebook's Messages feature you can send private messages back and forth with your Facebook friends and contacts, much in the same way you send emails. These private messages are stored in a threaded chronological arrangement and are accessible via the Messages icon on your Facebook homepage. From the ...
Click the conversation containing the message or messages you want to delete. If it is not listed on the initial Messages pop-up window, click "See All" to view all of ...