28.4.14

Remove authenticated system from google's 2 step verification...

You can remove computers from your set of trusted computers at any time. To do so, 

1. sign in to your account and go to your 2-step verification settings page.

2. Under the “Advanced” section, you’ll have the choice to remove the computer you’re using at the time or all other computers.

3. If you choose to remove other computers from your trusted list, those computers will automatically sign out of your account, and you’ll be prompted for a verification code next time you try to sign in from them.