If you want to keep your Facebook messages inbox clean but its filled up with hundreds of Facebook chat messages, it can be a nightmare – deleting each of them one by one. Unfortunately there is no option to delete your chat messages all at once but there are some add-ons for Google Chrome and Mozilla Firefox, and once those are installed you will get the “Delete All” button right inside your Facebook messages page allowing you to Delete all your chat messages with one push of the button.
This method is possible only from two web browser: Mozilla Firefox and Google Chrome:
Method 1: GreaseMonkey script on Firefox
Step 1: To make this script work, you need to have GreaseMonkey script installed in your Mozilla Firefox. If you don’t have it yet, you can download it from this page.
Step 2: Once installation is finished restart your browser. Then visit this website.
Step 3: Click Install green button located in top right corner of web site and install it.
Step 4: Once the add-on is installed restart your Firefox browser again.
Step 5: Now open Firefox again, visit your Facebook page with your chat messages and you should see a new “Delete All” button.
Step 6: Click on that button and on confirmation window that pop-up confirm your action.
Method 2: Extensions for Google Chrome
Step 1: Now if you are using Google Chrome as your main web browser, you need to download and install add-on from this page.
Step 2: Once its installed, simply visit your Facebook page with your chat messages and you should see a “Delete All” button.
Step 3: Simply click on that button and all your messages will be delete.
Note: By using this button you will not only delete your chat messages but your regular messages as well, so be very careful.