Hi, I swapped out my iPhone 5s due to a warranty issue and the replacement has an intermittent clicking sound when the home button is pressed. It's almost as if there is some sugary substance that was causing the button to be harder to press if the button hasn't been pressed in some time and one that also causes a loud clicking. After the first click the sound goes away as if the sticky substance was loosened. BTW, I am very careful with my iPhone and have never had any liquid substance dropped on the home button. I read another thread dealing with clicking but not sure if this is the same problem. Is it a design defect? Should I attempt to clean it with some swab and ethyl alcohol? Thanks.