I‘m always losing my keys so I was super-thrilled to find this idea at technabob over the weekend.
I couldn’t bring myself to drill through a lego piece (!) but after raiding my sons lego box I found the perfect bit to attach the key to (lego part number 3176). (I’ve just ordered six more of these bits through ebay so my sons and I can make a key holder for my hubby for fathers day ^_^).
You can have fun customising this keyholder in any way you want. We stuck a stormtrooper minifig on the top of ours…he is the new guardian of the key…which means I don’t have to accept responsibly for lost keys any more…yay!