To erase your iPod tap Settings > General > Reset > Erase All Content and Settings or use iTunes:
1.Connect your device to your computer using the cable that came with it.
2.Select your iPhone, iPad, or iPod when it appears in iTunes.
3.In the Summary panel, click Restore.
4.Click Restore again to confirm that you want to restore your device to factory settings and delete all data and content. iTunes will download the device software file and restore your device.
5.After your device is restored to factory settings, it will restart. When it does, you’ll see the "Slide to set up” welcome screen. Follow the steps in the setup assistant. You can set up your device as new or use a previous backup. If you restored an iOS device that has cellular service, it will activate after you finish setting up your device.