Shred is what I used when destroying a bunch of old drives.
Then I disassbled them to pull out the magnets and platters (because they’re shiny and cool). A couple had torx screws that I didn’t have the right end for so I ran a hdd magnet over the surface and scratched them with a screwdriver.
I have an HP 800 G4 arriving in the mail any day now. Right now I run most of my stuff on a pi3, including openvpn, transmission, minidlna, grafana, backuppc, and postgresql. I’m looking forward to porting all of that, plus suricata and dnsmasq, onto the G4 when it arrives.