How do we DELETE this new Rails 2.0 "Cookie Store"?

In the past, I would run this code to clear my session and cookie
variables;

  def clear_session
    session[:user_id] = nil
    cookies[:user_id] = nil
    cookies[:password_hash] = nil
  end

I would then go into my \Docs & Settings\user_name\cookies and clear
out the cookie file.
Now, in Rails 2.0 (using the new SECRET key) I can't seem to LOCATE?
what file this is being stored in so I can;
1. Clear it out (in code)
2. Delete it manually
I expect this is a common question.
Thank you,
Kathleen