Find my iPhone found my old mac that I sold should I erase it?

I sold my macbook air about three years ago and today I was setting up my new 6s and went to set up find my iPhone and it shows that mac as one of my devices about 400 miles away. I thought I erased it before I sold it but I guess not. So since he's using my find my iphone what else of mine can he use? And should I erase the mac to get him off my find my iphone? I have no way to get in touch with him.

Sign in to the icloud.com site, select the computer under "All Devices", Click "Remove from Account"Click "Remove" and follow the instructions. Your settings in the computer don't give access to any private info. All you are seeing is the location because you registered it through iCloud as your device and didn't unregister it. This takes it out of their system.

Do NOT follow the "Erase Mac" steps, as you will create a very unhappy person who bought your computer. You will wipe out all of his/her settings and preferences. It is not supposed to actually erase the entire hard drive, but anytime you mess with preferences, you run that risk as well.