It would probably have to be the original receipt from Apple.
Without being able to have the signed-in owner to remove the account information, and without the original receipt to get Apple to reset the device, they are useless to you. Get a refund or recycle them.
Read this article about removing Activation Lock --> How to remove Activation Lock - Apple Support Unless you have the account information that set the lock, the original receipt from Apple, or can demonstrate legal inheritance from a deceased owner, you cannot remove the lock; recycle the device.
From the very bottom of Apple Trade In - Apple :
"Does Apple offer recycling?
Yes. Apple Trade In lets you recycle any Apple device (including devices from Apple-owned brands) at any Apple Store and on Apple for free. That includes your batteries and old electronic products as well as free, on-demand packaging recycling for our commercial, education, and institutional customers. When we receive your device, it will be thoroughly inspected to determine if components can be recycled or reused. Whether recycled or reused, all activities relating to the processing of your device will be managed in an environmentally responsible way."