You may want to set Flash so sites can't store anything on your computer at all. I think you do that by hitting the second icon (Global Storage Settings) and moving the slider to none. You can probably also move the slider to none in the Website Storage Settings (the sixth icon, which is the one where you clear your storage). If things work right, sites will still be listed, but they won't store anything. If you have a Mac and your Flash is up to date, you'll have a Flash System Preference pane. Go to System Preferences (via the Apple Menu), and choose Flash Player (in the "Other" category). Under the Storage tab, choose "Block all sites from storing information on this computer." I've been blocking all Flash storage for quite a while, and nothing that I know of has broken because of it.