Make a little airtight container from an empty soda/water bottle and a nickel.
Step 1: What it is -
A small, air-tight container.
What's it for?
You put stuff in it.
Step 2: What you need.
empty soda/water bottle
Knife or razor blade
Dremel, for touching up the saw cut
not pictured - a clothes iron is nice, but not necessary
a US 5 cent piece, otherwise known as a nickel
Step 3: Prepping the bottle
First, plug in the glue gun. You want the glue to be hot as possible when the time comes.
Now, use the knife to remove the little plastic strip around the bottle neck.
Step 4: Cutting
Using your saw, cut the bottle neck at the spot that the plastic strip used to be.
Step 5: Finish with Dremel
Here is the finished piece. I used a Dremel with the tungsten carbide tip in order to even out the saw cut. I find the easiest way to do this is to place onto a flat surface and rotate while holding the dremel bit against the piece.
I left a very slight raised "ridge." I find this makes it easier to use.
Step 6: The nickel
Now place the piece onto a flat surface. If you have a clothes iron, you can use it to heat up the nickel. Here comes the real magic. Put the nickel in.. It's a perfect fit!
Step 7: Gluing
Now squeeze out a good gob of glue onto the nickel. Don't get glue on the sides of the bottle neck! This will only cause a disgraceful mess. Get it onto the hot nickel, and it will flow in an even layer. Make sure you get enough glue the first time... don't add more glue later, or it won't be an even surface.
If you mess up.. like I just did... then you can place the whole shebang on top of your overturned clothes iron at medium heat. Don't use the highest setting, like I did... I just found out that the plastic turns white when it gets too hot! :)