Managing search history in YouTube is simple. Either the selected video searches can be cleared or the entire history can be paused or cleared.
Here is how to do it :
Sign in to YouTube account and go to Video Manager. Or click on the blue square at the top right and next to account name, then select “Video Manager”.
Next, choose “Search History”. This will show a list of all the videos searched for so far in YouTube.
Either click on selected videos and hit “Remove”, or choose “Clear all search history”. To turn this off so that no more search history is accumulated, select “Pause search history”.
All done.