Facebook, by default, doesn’t provide ‘delete all’ button to erase all Facebook messages in your account. You’ll have to go to each and every message, open it and then delete it. This is a bit tiresome if you’ve plenty of messages in your Facebook inbox. However, for every problem there will be a solution.
In order to delete all messages on Facebook, a Google Chrome extension called “Facebook Fast Delete Messages” will come handy. Once installed, you’ll see new “Delete All” button next to the “New Message” button in your Facebook account.
This option will help you delete or remove all messages from your Facebook profile in a single click.