There are two totally different types of cookies that can be stored on your computer. As well as the session, first party, and third party cookies that your browser provides controls to handle, Flash also provides a completely separate way to save cookies on your computer that can even be shared between different browsers on your computer.
While you may have worked out the appropriate settings in your browser so as to control the browser cookies that web pages may want to use, chances are that you haven't even realised that Flash cookies exist. Some sites even use Flash cookies to recreate the browser cookies on your computer thast you told your browser to delete.
Since Flash is a browser plugin that can be installed in any browser the browser itself doesn't contain any way to access the settings to control Flash cookies on your computer. Instead the control panel is a Flash file itself that can be accessed from Adobe Flash Player Help. Simply run the Flash file on that page from any of your browsers and select the settings you want to have apply to all of the Flash that you allow any of your browsers to run.
Options that this control pane provides for you include determining which sites running Flash are allowed to access the camera and/or microphone on your computer, how much space sites can use to store Flash cookies,and how often to check for updates to Flash.
If you allow Flash to run in a browser on your computer then you should take a look at these settings to make sure you are not giving web sites access to do things on your computer that you would rather they didn't do.
Note that you can also right click on a single Flash object and select "Settings" to change the settings for that specific object.
This article written by Stephen Chapman, Felgall Pty Ltd.