How to 'wipe' an old ipad mini

What to do before selling or giving away your iPhone, iPad, or iPod touch

What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

Verify that your ios device is free of the activation lock.

How to check if the activation lock is active on a device

iCloud can’t find that page

Here is some further info.

--  Learn what to do if your iOS device is lost or stolen.

--  Learn about Find My iPhone Activation Lock.

--  If you registered your device with Apple, you can unregister it at My Support Profile.

If for some reason you try to login too many times to the ipad, it will freeze up.  & as you know, low you will be to recover.

You do want to  be the first to set the Activation lock.  This way you can at least restore you iPad should it get locked out.

Activation lock

Find My iPad

"With iOS 7, Find My iPhone includes a new feature called Activation Lock, which is designed to prevent anyone else from using your iPhone, iPad, or iPod touch if you ever lose it. It starts working the moment you turn on Find My iPhone in iOS 7."

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Undoing the Activation lock

See Texas Mac Man post in

I have restored a school ipad and was set… - Apple Community

Check this link...

What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

Here is what to do to wipe an iPad:

• Turn off find my by going to Settings -> [your name for your apple id] (it is the one at the top) -> Find My -> Find My iPad and turn Find My iPad off
• Rest the device by going to Settings -> Reset -> Erase All Content and Settings and follow the steps to erase the device

These changes will ONLY affect the old iPad mini, and I would suggest that you backup your old iPad if you have not already by going to Settings -> [your Apple ID name] -> iCloud -> iCloud Backup. This will backup all of your things from the old iPad to the cloud that you can use to set up the new iPad if you have not already done so.

If you have any questions or something does not seem to work, reply to this comment and I will do my best to help. Good luck!