There’s a vulnerability in Master Lock branded padlocks that allows anyone to learn the combination in eight or fewer tries, a process that requires less than two minutes and a minimal amount of skill ...

Most consumer-grade locks aren’t that secure. To wit, if you ever need to open a basic padlock or combination lock without a key, all you need is a soda can, a boxcutter, and a little precise cutting.

How to Make Safe with Combination Lock from Cardboard For this project you need cardboard, glue gun and few wooden sticks.