In the sidebar, select the storage device you want to erase, then click the Erase button. If you want to erase any other type of storage device: Double-click Disk Utility in the /Applications/Utilities folder. Note: If you want to get your Mac ready to trade in, sell, or give away, and your computer is a Mac with Apple silicon or an Intel-based Mac with an Apple T2 Security Chip, use Erase Assistant.