It is actually very easy. First download the latest Firefox. Then disable username and password storing. When you want to erase your trail just go to Tools->Clear recent History, and select Everything, then view details and select all the stuff. Then go to:
Code:
http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager07.html
And delete all websites (this deletes Flash cookies).
After that change IP.
You can skip the whole things, by doing stuff in the Privacy Mode, activated with Ctrl+Shift+P. After you are done, exit the Privacy Mode and clear the Flash Cookies.
I am doing above described manual cleaning for two years now, and NEVER had any problems, with any site, even the most stubborn ones. So, if some of sites discovered your credentials, than you obviously missed something.
P.S. I don't use IE, not only because it sux, but also because it is hard to control, and always saves data somewhere else.
P.S.S. It is understood that you don't have any kind of crap "enhancements" such as Google toolbar or something similar. It is also recommended that you do operations one site at the time, and have all suspicous application closed (such as Google Earth or Picassa).
You know what would be great, is if someone could come up with a "wash list" - a list of all things, such as
-cookies
-temp internet files
-flash objects
-IP address
-session variables
-a million other things I'm forgetting or aren't even aware exist, etc
Of what you need to clear between logins/activity.
This would apply to not just youtube, but also facebook, squidoo, twitter or any other social media site that has the problem of tracking people in order to prevent spam/abuse.
