Oh no! The power has gone out, and your flashlight is dead – and it only uses D batteries. There’s still a solution even if you don’t keep spare D batteries lying around the house. Place a couple C batteries into the compartment, and fill any wiggle room on either end with aluminum foil. This will allow the smaller batteries to connect, and power the flashlight. It won’t be as bright as if you had the right batteries, but some light is better than no light!