afaik, actually wrapping the phone in tinfoil blocks the signals pretty well. try it, you can't call a phone wrapped in tinfoil. if you have a tinfoil lined ba

afaik, actually wrapping the phone in tinfoil blocks the signals pretty well. try it, you can't call a phone wrapped in tinfoil. if you have a tinfoil lined bag (like a thermo lunchbag), it's even easier than removing the battery.