[gaijin]

You could drop that sucker in a mini-potato chip bag (those thing METAL types) and be fine, I think.

Here’s an experiment that will convince you of the value of a Farraday Cage:

Put phone A in a microwave, door open. Call the phone, observe ring.

Close the door of the OFF microwave:

Call the phone. It does not ring.

Those are the effects of a (small) Farraday Cage.

[expatpat]

You need more than that - you need a cage made of mu-metal because the EM signal has a magnetic component which also needs to be blocked, in addition to the electrical component.