5 Viral Car Key Hacks That Don't Work (And What to Do Instead)

Myth #1: Put Your Car Key in the Microwave

This is the big one — the "automotive microwave" trick or the "microwave oven for car" search. A viral YouTube video claimed that putting your car key in a microwave for a few seconds "resets the chip." Millions of people have searched for this. Thousands have probably tried it. We get calls about it at least once a month.

What actually happens: The microwave's electromagnetic radiation heats the metal in the chip and circuit board to several hundred degrees in seconds. The transponder chip — the tiny passive RFID component sealed inside the key head — is permanently destroyed. The battery contacts warp or rupture. The plastic housing melts. And if the microwave has any metal inside it (which the key does), it arcs — sparks, smoke, and sometimes fire.

You started with a car key that had stopped working. You end up with a lump of melted plastic, a broken microwave, and a bigger bill than if you'd just called us in the first place.

But we understand why people try it. Your key's dead. It's 11pm. A microwave feels like a free fix that takes 10 seconds. We get it. Here's the deeper dive — read the full explanation of why the microwave trick is a myth and what to do instead.

Myth #2: Wrap Your Key in Tinfoil to "Reset" It

This one has a grain of truth that makes it extra convincing. Wrapping your key in tinfoil does block radio signals — that's literally how a Faraday cage works. The myth says you wrap the key in foil, wait 30 minutes, unwrap it, and the key has "reset."

Why people believe it: Some cars (notably older Renaults and Peugeots) have a known issue where the key fob and the car's receiver get "out of sync." Removing the battery for 30 minutes allows the key's internal circuit to fully discharge, and reinserting the battery causes the key to re-sync with the car on the next button press. Wrapping in tinfoil doesn't do this — it just blocks the signal while the foil is on. The moment you unwrap the foil, the key transmits exactly as before.

The tinfoil does have one legitimate use — if you have a keyless-entry car and want to block relay theft while the key sits at home, keeping your key in a Faraday pouch (or wrapped in several layers of tinfoil, honestly) blocks the signal and stops relay attacks. But it won't fix a broken key.

Myth #3: Put Your Key in the Freezer

This one sounds like it came from the same person who invented the microwave trick — except in reverse. The theory: freezing the key somehow "resets" the chip or "shocks" the electronics back to life.

Here's where it gets interesting — there IS a scenario where cooling a car key can temporarily help. Older Honda and Toyota keys sometimes suffer from a failing solder joint inside the transponder chip. When the key warms up (from being in your pocket, or in direct sun on the dashboard), the metal expands and the cracked joint loses contact. Cooling the key causes the metal to contract and the joint makes contact again — temporarily.

But the freezer is the wrong way to do it. Freezing introduces condensation when you take the key out — moisture inside the circuit board causes corrosion and permanent damage. If you suspect a heat-sensitive fault, just leaving the key in a cool room for 10 minutes achieves the same thing without the moisture risk. And it's never a permanent fix — the cracked joint will fail again, usually at the worst possible moment.

Myth #4: Run a Magnet Over the Key

The idea is that a strong magnet can "reset" the transponder chip inside the key. This myth comes from old computer lore — back when floppy disks and CRT monitors could be affected by magnetic fields, people assumed the same applied to car keys.

Modern car key chips are not magnetic. The transponder is a passive RFID chip — it uses radio frequency induction, not magnetic storage. A magnet will not reset it, reprogram it, or affect it in any useful way.

But it CAN cause damage. Older car keys (pre-2005) sometimes have a magnetic stripe or a magnetically-coded immobiliser pellet in the blade. A strong enough magnet — like a neodymium hard-drive magnet — can corrupt these. And the remote fob's battery contacts are thin metal: a strong magnet may displace or bend them, causing an intermittent connection.

Myth #5: Spray WD-40 Into the Ignition Barrel

This one is especially common — and we see the damage from it regularly. The ignition starts feeling sticky, the key doesn't turn smoothly, someone says "just spray some WD-40 in there."

WD-40 is not a lubricant. It's a water-displacement spray (that's what WD stands for) and a solvent. It'll temporarily free up a sticky ignition by dissolving whatever gunk is in there — but it also strips away any remaining proper lubricant, leaving the lock wafers dry. Over the next few days, the WD-40 attracts dust and grit, which mixes with the residue to form a sticky paste. The ignition feels worse than before.

What's worse: modern ignition barrels contain electrical contacts for the immobiliser reader coil. WD-40 is a dielectric — it can coat those contacts and interfere with the signal between the key's transponder chip and the car's immobiliser. You go from a sticky key to an engine that won't start at all.

The correct product is a graphite-based lock lubricant — specifically designed for lock cylinders — or nothing at all. If the ignition is sticking, the internal wafers are likely worn and the barrel needs replacing. Lubricant buys you a few weeks at most.