Google Chrome has added the option to delete Flash cookies. Flash cookies are another type of information saved by certain websites on your computer. You can clear these information along with the regular browser cookies, just by visiting Wrench > Tools > Clear browsing data and selecting "Delete cookies and other site and plug-in data."
As of now, this option is available to Dev channel users only, but will land to stable channel (regular version) soon.
Flash cookies, or Adobe Flash Player Local Shared Objects (LSOs), are much similar to browser cookies and saved by websites on users’ system. LSOs are generally used for tracking purposes. Surprisingly, Flash cookies never expire and have larger storage capacity.
How to delete Flash cookies in Firefox
Firefox users can use BetterPrivacy add-on to review, protect and delete Flash cookies individually.