[cctalk] Mac SE disk cleaning

[Brian Knittel via cctalk]

Passing on a request: anyone know of a way to erase user data off a Mac SE hard 
disk that will leave the disk and Mac OS intact? The machine works and could go 
to a new home but has privileged medical data on it so just deleting files 
isn’t sufficient — the free space has to be overwritten. Are there any 
utilities available on floppy disk that could do it? Plan B is taking a 
sledgehammer to the drive, but seems a waste to go right to euthanasia if 
there’s another option.