The Old Hollowed-Out-Book Trick
If the sides of the books will be visible, fold back the covers of the books on the left and right sides of the assembly before cutting. Build a plywood box for the secret compartment to fit the opening and glue the book parts to the box with construction adhesive. The disadvantage to this hidden compartement? You can see inside the box on low shelves, so you need to display it so the opening is above eye level.
Right Out in the Open
Good Venting Is Key
Stick a magnet to a spare house key using hot glue, and tuck the key up out of sight inside the dryer vent hood. If your vent hood is aluminum or plastic, glue a magnet to the inside of the hood as well as the key. Check out our ultimate guide for finding secret hiding places in your home.