I boot Finnix and use dd if=/dev/zero of=/dev/sdx to wipe out drives. Most drives can be wiped out overnight. That fable about needing multiple passes is not true:

https://datarecovery.com/rd/why-does-it-take-multiple-passes...

If a drive contained state secrets, I might use /dev/urandom instead of /dev/zero, but those kinds of drives are probably just shredded.