My old Macbook Pro gone; the newer one puts my Apple ID at device limit
My current Macbook Pro is the fifth Mac registered to my Apple ID. My previous MBPro suffered a fatal hardware failure (overheated) and cannot Startup to remove its registration. I have a similar problem with my current iMac, which replaced a much older iMac. How can I un-register those out of use Macs from my Apple ID?
MacBook Pro, OS X Mavericks (10.9.2)