Deleting numerous messages on Messenger is not as easy as deleting emails since Messenger actually intends to keep conversation history. In order to delete messages you have in your account you need to open messages from your sender one by one and then you will proceed to “options” and start choosing messages that you wanted to delete.
If you’ve got plenty of messages, this process can surely be very tiring and time consuming. You can just remove messages from message list. However doing this won’t delete the messages permanently. The messages will be archived instead and reappear if a person sends messages again.
This is where fast delete all messages tool comes handy. This is a Google Chrome extension which allows you to delete messages with one click.