This was a fun project that my kids loved doing to get ready for our upcoming WDW trip: Find and shine pennies! Find all-copper pennies~ Go through your change jars and let them hunt all pennies that are dated before 1982. These are 100% copper and make the best flattened pennies. (The newer pennies have zinc in them and it makes a gray streak when flattened.) Set out 3 plastic bowls: 1st bowl: with about 1/4 cup of ketchup. Let the kids soak the pennies in ketchup for a few minutes. Completely kid safe and it works. It's a fun & messy project and they won't believe it will shine a penny. Watch their faces when they reallize it IS working. 2nd bowl: with some plain baking soda. Dip the ketchupy penny in and rub between fingers. This gets the remaining tarnish off and makes an icky paste that they'll love squishing in their fingers. 3rd bowl: water. Drop them in to wash all the ketchup and baking soda off, and dry on a clean towel. Another poster suggested collecting empty film cannisters or M&M "Mini" tubes for carrying your un-flattened pennies: putting 1 penny together with 2 quarters so that the correct change will always be handy for the machine. All I can say is that my kids had a blast doing this project!