My Treo makes a rattling sound, how do I stop it?

From TreoCentral

Q: My Treo makes a rattling sound, how do I stop it?

A Treo 600: Many people have reported that their Treo 600 makes a slight rattling sound. Some have speculated that it is caused by the sound on/off switch at the top of the unit. Try holding the switch and see if the unit still rattles. Besides the sound that it makes this does not seem to impair the functionality of the phone or the button in any way.