Choose from:
[1]. " if you have an ios device older than the ios 6.7 os or bigger, this can be done by clicking " apple device manager " or clicking " devices " from your device's dock. Turn off the device you're going to use the cleanest find-appropriate system cleaner..
[2]. " turn off your apple screen (which you have accessible through your ios device). If you don't have an ios device, you can plug one end of the usb cord into the port on the outside of your ios device..
[3]. " unplug the power cord from the back of your imac. Additionally, unplug any other devices that are connected to your imac like speakers and hdmi cords..
[4]. " Press and hold the power button. Once it turns off, press and hold the power button until the apple logo appears..Choose from options above and answer: What most naturally follows?

How to clean an imac screen
Shutdown and unplug your imac.
Click the apple icon in the upper left corner of your imac screen. Then click " shut down.
Answer:
[3].