StumbleUpon is a free website sharing service that allows you to promote your favourite websites by submitting them to the StumbleUpon network. You can download and install the StumbleUpon toolbar, which has a built-in search engine to search the submitted websites. Due to personal preference or privacy issues, you may wish the clear the search history so that another user can not see the sites that you viewed through StumbleUpon. You can set the toolbar to delete your history each time you close your Internet browser.
Launch your Internet browser.
Log into your StumbleUpon search bar if you are not automatically logged in.
Click the "Tools" menu, then click "Toolbar Options."
Navigate to the "Search & Tagging" tab.
Place a mark in the box next to "Clear search history upon exit," then click the "OK" button. When you close your Internet browser, this will clear your StumbleUpon search history.