Firstly, you should be aware that the majority of modern cell phones include several microphones in order to enhance the audio output and eliminate background noise. A microphone is typically found at the bottom of the cell phone, on the top, and somewhere in the middle. Once you know where the mics are placed, you can start gently blowing to help remove any dust or dirt present there. Thereafter, gently begin wiping the first microphone with a brush or cotton ball. Then move the cleaning item you have picked slowly and repeatedly until you observe the last of the deposited dirt emerge.