Want to keep a spare set of keys in your wallet without them bulking it up? Grab an old credit card and a cutter, and you'll soon have a DIY key holder that keeps them together and doesn't bunch them up.
As anyone who carries spare keys in his wallet will tell you, those little things have a way of moving about and lining up one next to the other. Pretty soon, your wallet resembles this:
To avoid that, MateFrio at EDCForums came up with a smart way to reuse an old credit card or any similar card. You'll basically be cutting two strips in the card and sliding your keys through them -- with the heads on opposite ends, you can fit two keys easily and they won't move around.
MateFrio has a few tips you should check out at the full post below, like practising first on a card you don't care about, and bending the card after your first slice so it cracks for a clean cut.
MateFrio's DIY Wallet Key Holder [EDC Forums]