Wipe a Chrome device and restore

1. Turn off the Chromebox.
2. Put a paperclip (or pushpin) into the recovery button hole. 

   
   

3. Press down the recovery button with a paperclip while turning on the device. Once you press the power button, you can remove the paperclip
4. When you see the yellow exclamation point on the screen, press Ctrl + D on the keyboard
5. Press the recovery button with the paperclip again. The device reboots and displays a red exclamation point.
6. Press Ctrl + D. The Chromebox reboots and starts the transition to developer mode which clears all local data and takes approximately 10 minutes.
7. At the Welcome screen, select English as the language, US as the keyboard, and Ethernet as the network
8. Click Continue
9. Click Accept and Continue
10. When you see the Enterprise Enrollment Screen, enter joinchrome@arbor.edu for the email address and joinchrome as the password
11. You should see a screen that reads "Your device has been successfully enrolled for enterprise management". Click Done

From https://support.google.com/chrome/a/answer/1360642?hl=en