Earlier today we showed you how to kill your mobile phone speaker buzz by applying small metal sleeves to your speaker wires. If that's not an option for you (say you've got built-in speakers), one iPhone user has built an iPhone anti-radio interference shield—which is a fancy way of saying "sliced open can of Red Bull." In a nutshell, the author opened up an empty Red Bull and taped it to the back of an iPhone dock. The result: about 180 degrees of interference-free air. Anything in front of the shield is still susceptible to buzz, but according to the author the Red Bull shield does the trick for anything behind the shield. If you give it a try, let's hear how it works out in the comments.