Does a biscuit tin stop a car key signal?

Can a Biscuit Tin Block Your Car Key Signal?

With the rise of keyless entry systems, car owners are increasingly concerned about relay attacks—where thieves amplify the signal from your key fob to steal your vehicle. To protect against this, many turn to Faraday pouches, specially designed with metal lining to block electromagnetic signals. These pouches are reliable and widely recommended by security experts.

But what if you don’t have a Faraday pouch? Some suggest using household alternatives, like a metal biscuit tin. The theory makes sense: metal can interfere with radio waves, potentially blocking the fob’s signal. In practice, a biscuit tin might offer some protection—but it's not guaranteed. Unlike purpose-built Faraday bags, tins vary in material, thickness, and seal tightness. A loose lid or thin coating could let signals slip through.

Still, in a pinch, placing your key fob in a metal container like a biscuit tin is better than leaving it exposed on a hallway table. It adds a layer of difficulty for potential thieves. For maximum peace of mind, though, a tested Faraday pouch remains the smarter choice.

One thing is certain: storing your key fob near the front door or in an open space makes it vulnerable. Whether you use a Faraday pouch or improvise with a biscuit tin, taking simple steps at home can go a long way in keeping your car secure.