Here we will use an Extension to delete all Facebook timeline posts. Remember it won't be deleting your friend's tags but it will delete only your post. Follow the below steps and clean your Facebook timeline post.
How to Delete all the Old Facebook Post From Your Timeline
1) First of all open your Browser then install the extension.
2) Install Facebook delete my Timeline Post for Google Chrome Users and install Facebook Delete my timeline post form Mozilla Firefox user.
3) Now go to your Facebook Timeline and click on the extension button on right hand top.
4) Now it will ask are you sure to proceed then click on OK button.
5) Now just wait and see the extension