You don't. It is the owner that chooses the information that will show when they are held up to an iPhone and you cannot get any other information than want they want to disclose. The owner can still track the AirPods so they know where they are. It is recommended to turn them in at a local lost & found or even a police station, so the owner will see where they are and retrieve them. While I understand you have good intentions, it may not be a good idea to hold on to them where you get a knock on your door from the owner wondering why you have their AirPods.