Cannot Sign In

For the life of me, I couldn't figure out how to fix this.

I got used ipod touch and wanted to set up specific gmail account as AppleID. I wanted to enable iCloud, I ended up got "Cannot Sign In... The maximum number of free accounts has been activated on this iPod touch."

How do I remove the existing account off from this device? Hard/soft reset won't work and I learned something new from Apple tech support which I strongly disagreed that said a device is limited to three accounts, that's it.