This video shows you how to use a Swiss Army knife can opener. It is easy to confuse the can opener with the bottle opener. The can opener has a small screwdriver tip and a sharper edge. Cans of spaghetti are good for a quick meal on the train. Put the bottom part of the can opener underneath the lip of the can. Use leverage to poke the top part of the opener through the lid of the can. Move the opener backwards a little and push through again. Keep doing this all the way round the top of the can until you can open the can easily. That's it!.