Delete old system folders

[SoundChaos]

I am running 10.12.6 and have 5 old hard drives connected to my Mac, each of them had previous OS on them at one point or another.. I am trying to keep all the user/application and other data on them, but remove the OS system and library folders. The problem is, as soon as they get put in the trash, a new one is created on each drive that has many empty subfolders. I don't want any of these drives to show up as potential startup disks anymore. How do I clean these drives without reformatting?

I was able to mount all the hidden EFI partitions on them however, and successfully removed all the EFI folders.

 

[Taz Mangus]

I am running 10.12.6 and have 5 old hard drives connected to my Mac, each of them had previous OS on them at one point or another.. I am trying to keep all the user/application and other data on them, but remove the OS system and library folders. The problem is, as soon as they get put in the trash, a new one is created on each drive that has many empty subfolders. I don't want any of these drives to show up as potential startup disks anymore. How do I clean these drives without reformatting?

I was able to mount all the hidden EFI partitions on them however, and successfully removed all the EFI folders.

One way that might wok is to open the Terminal and delete the folders manually from Terminal.

 

[Fishrrman]

What I would do:

First, disconnect ALL of the external drives.

Then, RE-connect ONE of the drives.

Then, let its icon mount on the desktop.
Type "command-i" to bring up the get info box
Go to the bottom, click the lock icon, enter password.
In "sharing and permissions", put a check into box, "ignore ownership on this volume".
Close get info.

Now, you should be able to delete ANY folder on the drive, including the System folder(s).

When done, DISconnect this drive and put it aside for now.

Connect the NEXT drive, and repeat the process, etc.

Does this work?

Note: it might be good to make invisible files VISIBLE while doing this, and you could delete other system-related files, as well.

Be sure to EMPTY the trash before you disconnect the drives.

 

[Partron22]

OS Library folder includes "Application Support" folder.
Your Apps on your old drives may not function without the info therein.
Simply gutting the System/Library is likely to cause messes.