Grab your supplies. I bought new cards but you can use old ones.
Put your cards together in 1 pile, then separate a pile of 9 and a pile of 8. These will be your lid and base.
Choose a card for the bottom of your lid and add it to the pile of 9 so you have 10.
Now pick another one for the very bottom of the deck and put it on the pile of 8.
Now flip that same pile and choose a card you want to see inside the box at the bottom, and put it on top. You should now have 10 in both small piles.
Now glue all of the cards in the big pile together, focusing mainly at the edges.
Now do the same with the other 2 piles keeping them separate. You can put glue on the entire card this time.
When the big stack is dry, cut with the X-acto knife into the pile. Cut all the way through.
Once you're all the way through the big stack, glue the base onto the bottom.
I used clamps to be sure everything dried straight.
When it's all dry, fill it up!
Put on the lid.
And wrap the elastic around it to make it look like a regular deck of cards.
YOU'RE DONE! I hid my gum in mine, but you can hide anything small inside it too.