1. Select the menu in the top right corner (≡).
  2. Click on Preferences or Options 
  3. Select Privacy & Security from the lefthand menu
  4. Go to the Cookies and Site Data section and click on the Clear Now

If you want to clear cookies only for the Convious URLs:

  1. Under Cookies and Site Data, click on the Settings
  2. Type Convious in the search bar and click on the Remove All Shown
  3. Click on the Save Changes button
  4. Close and reopen your browser