Welcome to another installment of our "From Trash to Treachery" series, where we explore creative ways to transform everyday household items into valuable tools for testing and improving security measures. With a focus on reusing and repurposing materials, we aim to provide you with cost-effective and environmentally friendly methods to keep your home and business safe. Join us on this journey as we uncover hidden security gems in the items you might typically discard!

Can your security stand up to an item found in every wallet? In today's world, ensuring the physical security of our homes and businesses is more important than ever. As part of our "From Trash to Treachery" series, we've been sharing innovative ways to use common household items to reveal potential security weaknesses. In this third installment, we'll focus on a simple, cost-effective method to create a tool that can help you identify potential security vulnerabilities in doors. We'll show you how to fashion a useful tool out of an old credit card that can reveal physical security vulnerabilities in doors – proving that there's more to card tricks than meets the eye!

To begin, gather the following materials:

An old credit card or similar plastic card (gift card, hotel key card, etc.)

A pair of scissors

A fine-tipped permanent marker

A ruler or straight edge

A file or fine-grit sandpaper

A small round edge (coffee cup, can, etc.)


Step 1: Planning and Marking

Let's start by marking the card at the following points.

Then with the help of our ruler and round edge we will layout our card.

Step 2: Cutting the Card

Carefully cut along the marked line using the scissors.

Step 3: Finishing Touches

To ensure the tool is safe and effective to use, use the file or fine-grit sandpaper to smooth any rough or sharp edges along the curve and the rest of the tool.

How to Use the DIY Credit Card Tool:

With your DIY credit card tool in hand, you can now begin identifying potential vulnerabilities in doors. To use the tool, follow these steps:

Identify a door you want to test for security weaknesses. Does it open toward or away from you?

If it opens outward, insert your hook end over the latch and gently press down and rock it forward.

If the door opens away from you, insert the C side and gently push it forward with a rocking motion.

If your door is not hung properly, or your hardware is outdated, the card will depress your latch and the door will swing open.


Creating a DIY credit card tool is a simple, cost-effective way to assess the physical security of doors. By identifying and addressing these vulnerabilities, we can take steps to strengthen our security measures and protect our homes and businesses from potential intruders. Always remember to use this tool responsibly and only on doors you have permission to access. Stay vigilant and keep your property secure!