I had an issue where I needed to reset all zDeviceTemplates back to their default.  I.E. remove all local copies.  The below script will go through all Devices (YOU MAY WANT TO CHANGE TO A SPECIFIC CLASS) and remove the local zDeviceTemplates.  This would also work for removing any other zProperty that you wish to remove.

for d in dmd.Devices.getSubDevices():
        if d.isLocal('zDeviceTemplates'):
                d.deleteZenProperty('zDeviceTemplates')