Gather your materials. You can choose either to use a cup (like I did) or a cylindrical container with a lid. Cut out a small sheet of aluminium foil, and make sure it is as tall as your container, in other words, fills your container completely when you curl it up.

Use your pencil and start poking holes onto your aluminium sheet. Hold the sheet firmly before poking holes so you won't accidentally tear or create extra big holes. If you're a star buff, you can also poke holes according to the constellations! After you're done, curl it up and slot it into your container.

Finally, you need to get a light source, preferably something you can on and off as and when you like. Note: If you're using a cup, make sure to use a flat piece of cardboard to cover the top and if you're using a lid, throw in the light source and screw on the lid. As I was in a hurry I just used an iPhone application called "Flashlight" as a temporary light source. And yep! Enjoy your new (and pretty) starry jar!