I love this idea to attach a rock to a bottle lid for hiding a spare key! Found at the blog Apartment Therapy, this is simply genius! We have a ring of river rock around a bush near the garage door, so we grabbed a memorable rock, an old medicine bottle, and the spare key. When it came to glue… I was unsure. I thought it might be difficult to open the child proof bottle with a huge rock in the way, so in the end I used a small strip of sticky back Velcro that I had on hand. I put the soft side on the top of the bottle, the rough side on the rock, and… Ta-da!