How To Clear Everything -:
1. First, click on the Facebook search bar on the top. A list of your all recent searches will appear on the screen. In the right corner, you see an EDIT button. Select EDIT and follow next steps.
2. Now you see Search History page on your screen. For deleting all search history click on Clear Searches button in the top right-hand corner of the page.
3. Select Clear Searches and your all Facebook Search History will be removed from your Facebook profile.