Bullets.
nice.
when i was a bochur, i shnorred some bullets from chayalim, and wanted to bring the back to the states. being to scared to pack them in my suitcase, i opened my alarm clock and replaced the battery with the bullets, it was just about perfect size, and i figured there is no way a scanner can pick up the difference.
on the way to the airport i had a panic attack, realizing that although 99% chance it would go unnoticed, if it doesnt, connecting explosives to a clock to bring on a flight might land me in hot water, so i just tossed it.