BOAC
I'll have a go.
I am on W7 so the routes may be different.
If you run C Cleaner it deletes the sol files associated with the cookies.
If you check the folders you will find the sol files have been deleted and presumably the cookies too.
However, when you go to the settings manager on the flash website and look at the visited websites list there are still entries there.
Now if you go back to the flash player folder:
Users\Name\Appdata\Roaming\Macromedia\Flash Player\macromedia.com\support\flashplayer\sys you will find a file settings.sol
Add this file to your c cleaner Options (advanced custom files to delete)
Tick custom files under advanced.
Run ccleaner and then the list of files on the flash website should be empty.
I know you are more PC savvy than me so apologies for the detail.
MC