 All that personal info just sits there, unless you delete it. Here's how. In the car's infotainment system, head into the car's Bluetooth settings. Remove your phone from the list of paired devices. This way, your contacts, call history, and other personal data won't be left for the next renter to see, or who knows who else. If you really want to play it safe, do a complete factory reset on the car's infotainment system. This wipes everything clean.