A Flash cookie (also known as a Local Share Object, or LSO) is a collection of cookie-like data that a Web site running Adobe Flash can place on your hard drive. Like regular cookies, Flash cookies contain information about when you visited the site, and may contain tracking and settings information.
Flash cookies are stealthier than regular cookies. Flash can install cookies on your computer without your permission by default. You can change the default setting for Flash cookies at http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager03.html ("Allow third-party Flash content to store data on your computer.").
Or, you can use CCleaner to clean Flash cookies when it runs. By default, CCleaner is set to leave Flash cookies alone.
To set CCleaner to clean Adobe Flash Cookies:
Note: Remember that cookies and Flash cookies are two separate things. Simply clearing the Adobe Flash Player setting will not set CCleaner to clean regular browser cookies.