January 05, 2012, 9:24 PM — Here's how you can eliminate all of your wall posts on Facebook without having to click each one individually.
1. Open Firefox (you'll need to use it to do this).
2. Go to the Mozilla Addons page and install Greasemonkey.
3. Restart Firefox.
4. Install the Facebook Scrubber script.
5. Click Install again when Greasemonkey asks for confirmation.
6. Go back to your Facebook profile page and hit refresh in your browser.
7. You should now see the Delete All Older Posts button on your profile page.
8. When you click the button Greasemonkey will warn you that you are going to remove all posts, comments, activities, etc that are displayed on your profile page. Click on OK if you wish to continue.
9. Keep hitting the button and/or refreshing the page until all of your wall posts are gone. Be patient as it may take a few minutes to get rid of all of your wall posts on Facebook.
That's it. Now all of your Facebook wall content is gone. This is a much easier and faster way of doing it than deleting each item by hand.
For more, see the original article at the link below.