El Capitan: How do I securely delete a Time Machine backup from an old Time Capsule?
Just replaced a 2nd gen Airport Time Capsule with a 5th generation Time Capsule (mid-2013 model).
The Time Machine backup is in progress to the new Time Capsule.
When it finishes, what is the secure way to delete any traces of the backup on the old Time Capsule? The goal is to clean it as if I were going to sell it.
Thank you
iMac, OS X El Capitan (10.11.2)