"Flash cookies," also known as local shared objects created by Adobe's Flash Player, have been notoriously difficult to get rid of because they never expire, users aren't notified about them when they're set, and they're stored outside the browser's control. Adobe's latest Flash Player update allows you to delete them through a new native control panel or using the web browser's privacy setting. This is true for all major operating systems: Windows, Mac and Linux.
Other critical security vulnerabilities are fixed by the update, as well. You can read more about that here: