You Need to Do More Than Delete Files on an External Drive to Make Them Permanently Disappear

There’s a trick to thoroughly wiping all your data before you junk your old external solid state drive—or even computer.
MUO on MSN

This is what happens to a file when you delete it from your SSD

Deleting a file means it should be gone for good. That's why most people assume that when you delete a file and then remove ...
Ars Technica

Using terminal to erase external SSD hard drive

The disk in question is disk04 - a 128 GB SSD drive in an external USB enclosure. I booted the Macbook from a X.11 USB install drive and there was an internal SSD drive as well. a simple fdisk ...