If you care about your privacy, then you must know that Facebook stores everything you do there including what you search for.
Here is a quick tip to delete all your facebook search history.
First of all, how can you see what all you searched. Go to your profile -> Activity Log -> Posts and Apps -> Select “Search”
Here you will find what all you searched with dates.
To delete all your search history from Facebook, click on ‘Clear Searches’ button at the top. You can also selectively delete items individually by clicking on the small cross sign that appear when you hover over any Facebook search history item.