Alternatively (since the little Flash UI sucks), in these two places-

Windows users:

  Documents and Settings/yourusername/Application Data/Macromedia/Flash Player/Shared Objects/your flash userid/
  Documents and Settings/yourusername/Application Data/Macromedia/Flash Player/Macromedia.com/Support/Flashplayer/Sys/

Mac users:

  Places/yourusername/Library/Preferences/Macromedia/Flash Player/SharedObjects/your flash userid/
  Places/yourusername/Library/Preferences/Macromedia/Flash Player/Macromedia.com/Support/Flashplayer/Sys/

Wow. I have flash cookies from over 700 sites.