Gas masks became a widely-known defensive measure during the air raid bombings in Britain during the height of the Second World War. Axis forces would occasionally forsake their usual high-explosive ordnance bombs in favour of chemical payloads designed to sicken their victims and cause panic. With a little guidance and some basic materials, you can build your own vintage WWII-style gas mask box complete with authentic instructions on usage printed on the inside and outside of the box.
Use the utility knife to puncture either one central hole or as many holes as you'd like to accommodate snaps across the top of the front panel of the box, just beneath the front edge of the lid. Make sure the holes are evenly spread apart and affix the snaps to the holes with the studs facing outward.
Cut the military canvas so that it can be fitted across the front edge of the cardboard box, where the lid opens. Attach it by snaps to the top flap of the cardboard box and add receiving-end snaps on the bottom edge of the canvas that will line up with the stud-ended snaps placed in Step 1. Your box can now be snapped shut to avoid losing the gas mask during transportation.
Cut small holes on two opposite sides of the box perpendicular to the lid, but close enough to the top of the box to avoid the strap interfering with the insertion or transportation of the mask. Attach the ends of the strap to the box by a set of at least two snaps per end, and your box is now portable.
Cut vintage-style paper into sheets that will cover one panel each of your box, as many panels as you'd like to cover, and inscribe them with instructions on using the gas mask, proper transportation or the legal use of a gas mask involving children. You can find examples of these instructions on military history websites. (See Resources 3) Attach the vintage paper sheets to your desired box panel with an even layer of rubber cement, making sure to glue down the edges as well to avoid paper cuts.
You can alternatively cover your box entirely in canvas to create a more militaristic feel, but civilian gas masks were delivered in cardboard boxes.