Get a grown up to brew a small amount of coffee (you’ll only need ½ cup for the activity) and save the grounds. Allow time for the coffee to cool. For younger kids, you may want to measure out the ingredients ahead of time, but older kids will enjoy measuring.
Stir together the coffee grounds, coffee, flour, and salt, until well mixed.
Knead the dough and then flatten it out onto the wax paper.
Use the can to cut out circles (or the cookie cutters/knife to cut out fun shapes).
Press the small objects firmly into the dough, to leave an imprint. Remove the object, and there’s your fossil! You can use a toothpick to poke a small hole near the edge of the fossil, if you want to hang it later.
Let the fossil dry and harden overnight.
You can hang it the next day, or use it in an archaeological dig!