This document explains how to clear the cache and cookies in Opera 9 through 11.
Click on the Opera button in the top left corner > Settings > Delete Private Data...
NOTE: You can also access this menu by holding Ctrl + Shift + Delete.
Click on Detailed Options to show the rest of the options. Make sure only the following are checked:
Click on the Delete button.
Click on Tools > Delete Private Data....
Click on Detailed Options to show the rest of the options. Make sure only the following are checked:
Click on the Delete button.
You will need to restart your browser for the changes to take effect.