Unless you have the account information that set the lock, or the original receipt from Apple, you cannot remove a lock; recycle the device. If you bought at an Apple authorized retailer you should have a valid receipt. If you bought this at a third party store reselling Apple products then ask them to ask Apple since it will be they to whom Apple issued the original receipt. Read this article about how to remove Activation Lock --> How to remove Activation Lock - Apple Support
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."