Flash are cookies or Local Shared Objects (LSO) and they are not deleted when you delete the cookies from your browser (unless you use a special add-on). Flash cookies like the regular cookies (txt files) contain some privacy information and can be used by some advertisers for tracking purposes. Unlike the regular cookies, LSO does not have a expiration date and the information inside can stay indefinitely. There are several ways to remove flash cookies:

1) Deleting them from the default folder where there are stored. The locations where they can be stored are :

• Windows XP:
  • For Web sites: C:\Documents and Settings\<user>\Application Data\Macromedia\Flash Player\#SharedObjects\<random code>\<domain>\<path>\<object name>.sol
  • For AIR Applications, C:\Documents and Settings\<user>\Application Data\<AIR Application Reverse Domain Name>\Local Store\#SharedObjects\<flash filename>.swf\<object name>.sol
• Windows Vista
  • C:/Users/username/<user>/AppData/Roaming/Macromedia/Flash Player/#SharedObjects/<domain>/<path>/<flash filename>.swf/<object name>.sol
• Mac OS X:
  • For Web sites, Macintosh HD:Users:<user>:Library:Preferences:Macromedia:Flash Player:#SharedObjects:<random code>:<domain>:<path from webserver>\<object name>.sol
  • For AIR Applications, Macintosh HD:Users:<username>:Library:Preferences:<AIR Application Reverse Domain Name>:Local Store:#SharedObjects:<flash filename>.swf\<object name>.sol
• Linux/Unix:
  • /home/<User>/.macromedia/Flash_Player/#SharedObjects/<domain>/<path>/<flash filename>.swf/<object name>.sol

2) Using Firefox addons. There are several Firefox addons which handle LSO. Such addons are Better Privacy & Objection.