Be careful when selling or transferring second-hand goods. IoT devices such as Amazon Echo have become widespread in ordinary households, and new devices are appearing steadily, so it has become commonplace to resell used devices that are no longer in use at Mercari. Amazon recommends that you reset your device to factory defaults after using the product to erase your personal information before selling or transferring it to others. However, simply resetting the device does not erase that data from this world. It is hypothetically possible that reselling the device will bring back the old personal information.