When Styrofoam is heated in the oven it will shrink a little and become hard like a plastic.
What you need
Clean styrofoam trays
Put your oven at about 170 degrees and increase the temperature (if no shrinkage is occurring) until it begins to start shrinking.
Paint your design with the paint on to the styro. Then cut out the ornament shape to the size you want.
If you are going to be hanging it then now is the time to place a small hole in the top before you shrink it.
Place the styro onto a oven tray and then stick it in the oven.
The shrinkage time will be based on the size of the piece and the heat of your oven.
These can be used for gift tags, name tags, necklace charms and heaps more.
This Project should be supervised at ALL times and only done in a well ventilated area.