The below message was located on the lockpicking 101 forum
If you take a trip to your local newsagent, you’ll find what are referred to as “Bulldog clips”. The are essentially the black clips (with silver removable handles) that are used to hold together sheets of paper.
They come in many sizes and I believe the largest is just over an inch thick, meaning they can hold an inch stack of paper. Once you clip the black bit onto the stack of paper, you can flip the handles down to lay across the paper. Anyway, I’m sure you’re aware of them.
The removable handle (which varies in size from clip to clip) can be taken off and used as a makeshift key for a set of handcuffs or thumbcuffs.
They work on the same principle as the bitted end of a genuine cuff key and can be inserted into the keyhole and turned to release the pawl, allowing the ratchet to move, opening the handcuffs.
The great thing about these clips is that the handle can be left on and the clip clipped onto the pocket or waist line of a pair of pants (basically anywhere) and if missed during the initial pat down after arrest, the handle can be removed and used to escape from the cuffs.
I have practised using this technique on both handcuffs and thumbcuffs and find it can open a set of cuffs in about 12 seconds (per cuff) when cuffed behind your back with thumbs up (as is standard position with all law enforcement and security).
Stay Safe.
A Bulldog or “Binder” Clip