WOW...I completely missed the "r" too. I read it as 'dry ice". As a matter of fact, I just told my wife about the "dry ice" trick and she looked at me funny. Now I know why as I read it completely wrong. I guess if you really think about it...if you put dry ice on a wet phone, I imagine the water in the phone would freeze solid but hey, I thought if someone posts it here, I believe it!
You can also bake them over night in a 150-175 degree oven too. Make sure you have it under control or you'll end up with a puddle of plastic or worse. Most of the plastics and components of a cell phone should take temps higher than that. Exercise this tip at your own risk.