Local Stored Objects (LSOs), or Flash Cookies, have become ubiquitous on most systems due to the extremely high penetration of Flash applications across the Internet. They tend to be much more persistent because they do not expire, and there is no built-in mechanism within the browser to remove them. In fact, many sites have begun using LSOs for their tracking mechanisms because they rarely get cleared like traditional cookies.
Win7/8/10:
%APPDATA%\Roaming\Macromedia\FlashPlayer\#SharedObjects\<randomprofileid>