This is a good project for a rainy day or if you are teaching children about coin designs. With the completion of the 50 U.S. state quarters and new designs being put forth for the other coin denominations, children will have a reference for changing coin designs. This project allows them to design and make their own fake coins. You can change the size and shape of these by varying the plastic lid used as a mould. Be sure to plan to start these on one day and finish them the next so that the clay can dry.
In the mixing bowl, combine the flour, salt, oil, alum, and boiling water. Stir to combine.
Knead the dough until all of the ingredients have been thoroughly mixed.
Press a small amount of dough into each mould. Use the side of the dowel to flatten the top.
Carve a coin design in the exposed portion of the dough before it dries.
Carefully flip the coin out of the mould and carve another design on the back or on the sides, if desired. This step is optional.
Let the dough harden overnight.
Cover the coin on all sides with aluminium foil and use your fingers to press the foil into the carved image on the dough coin. You can also paint the coin on all sides with silver paint and let it dry.
Use plastic lids in different sizes to make various coins. Try a small lid from a can of Pringles, a bottle cap, or a larger coffee can lid. Be sure to use a plastic lid that can be thrown away. Be sure to not press down too hard when creating the design on the back since it could mar the image on the first side.