In order to remove an apple device from the iCloud, be sure that the device has “Find my iPhone” turned off.
1) Open “Settings on the device
2) Choose iCloud
3) Set “Find my iPhone” to OFF
Using a PC, login at www.icloud.com using the customers iCloud credentials
1) Choose devices
2) Power the device off
3) Click the “Delete” icon for that device
The device should now be removed from the iCloud.