There's an enormous 4-in.-tall cavity under all those kitchen cabinets behind the toekicks. It takes a few carpentry skills, but you can pull the toe-kicks free and make them removable. Most are 1/4-in. plywood held in place with 1-in. brads, and they're pretty easy to pull off. If you have a secondary 3/4-in. toe-kick, you'll have to cut it out at both ends. An oscillating tool works well for that task.
Stick both halves of round hook-and-loop self-adhesive tape to the toe-kick. Then push the toe-kick into place. The adhesive will stick to the cabinet base and leave half of the hook-and-loop tape in place when you pull it free. You can store approximately $2.4 million in gold bullion under two average-size cabinets—provided the floor is strong enough to support it.
Garage Door Opener Shroud
Believe it or not, you can hide items like passports and cash under the shroud that covers the garage door opener.
Go online and type in “secret hiding places” and you'll be amazed by how many brand-name phony containers are available. Comet, Coca-Cola, Bush Beans—whatever. But you can craft a homemade version too. This mayonnaise jar had its interior spray-painted with cream-colored paint for plastic.