Tech,
I have no idea what 90 they use, very good question. I dont use the plugin Myself, so I cant give any advice
From what I read this plugin puts permanent "fake" cookies in, to block the real cookies from getting in. Im sure you already did some reading on it as you know about the 90 sites lol.
When this plug in is being used, those "fake" cookies cannot be removed until the users uninstalls the plugin, or so I gather.
Thats why I asked the original poster if he was using this plug in. As it might be the cause of his permanent cookie issue.
Saty