How to remove iPod from my devices

There is no need to remove it from your devices.

However, what you should have done was erase your personal information from the iPod before you gave it away. If you did not do that, and the iPod is a Touch (which can be signed into your accounts, for example email and the iTunes Store), you will need to change the passwords on those accounts in order to prevent the new owner using the account.

Any music left on the iPod is not owned by the new owner, but again you don't need to worry too much about that, especially if you are unable to contact that person as there is little you can do about it now. Eventually the owner will need to erase it.

The following Apple article gives you more information: What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

Look for it on “Settings -> Apple ID”, scroll all the way down in the Apple ID settings, and click “Remove from Account”, This will erase all data from the iPod and unassociate the device from your Apple ID.

Hope this helps!