Delete your browser cache. Best thing is to use 2 different browsers. With your main browser your playing your main account while you configurate your 2. browser in a way that it always deletes browser cache when closed. I believe Firefox has that function already builed in while Chrome needs a simple addon. Its a very basic function and about every browser should able to be configurated in that way. That way you can log in with a new acount every time your restarting your secondary browser.