Save your privacy using Bug Fix Auto Token android app, this app allows to delete auth token information, which is much dangers because hackers can steal your account information, when you connect to Wi-Fi spots. When you log in the device in Google services, the device is issue a login authentication token for communication.
In Google services, token is transmitted through an http protocol which hackers can steal in public wifi. This app includes account from Google calendar, Google Contacts, Google Picasa and other Google services, along with accounts on applications such as Twitter and Facebook. You can download this app from here.