First decide what you want to ‘clean’: the Data or System volume, or firmware? Then consider the methods of choice to perform that. Explained for Intel and Apple silicon Macs.
EACAS
It throws away the encryption key for the Data volume, effectively wiping all its data. It doesn’t alter the System volume, SSV, or the macOS installed.
You’ve set up your new Mac, and now need to prepare the old one for disposal, maybe to a friend, relative or someone buying it, or to go for recycling. What to do next,
There’s extensive experience in recovering deleted files from hard disks, and results can be surprisingly good. Recovery from SSDs is more tricky, and secure ‘wiping’ ensures nothing can ever be recovered, making good backups essential.
From the start of the fourth cycle in M4 Macs and the smallest ever, through the omission in macOS VMs, and QuickLook shortcomings, to the stealth firmware update.
Could old images be retained on a device or your Mac after you had securely erased it using Erase Assistant?
Step by step guide to passing your Mac on or recycling it. Use EACAS where available. Don’t use .AppleSetupDone which doesn’t work in macOS 14 anyway.
If you normally ‘clean’ install a new version of macOS, how can or should you do that with Sonoma or another recent version on a modern Mac?
A simple task: deauthorise an M1 Mac mini to hand on, then use EACAS to wipe it ready for its next user. But deauthorisation wouldn’t work.
If you plan to trade in or pass on your old Mac when you upgrade to a new one, there are pitfalls in ensuring you don’t lose any data, while ensuring your old Mac is completely wiped.
The Eclectic Light Company 