Wired recommends using a hammer.
4) The best approach? Hammer time. Hitting the chip with a blunt, hard object should disable it. A nonworking RFID doesn’t invalidate the passport, so you can still use it
The hammer might be the easiest but there are plenty of interesting ways a passport can accidently be smashed. It got dropped in the driveway and it got run over with the truck. I dropped a brick on it. Just make the accident plausible. Tampering with a passport is punishable by 25 years in prison.