Green cardboard (you can also paint regular cardboard green)
Green construction paper
St. Patrick's Day stickers
Trace a circle around your oatmeal container onto green paper. Glue this circle to the top of your container.
To make the brim of the hat, trace a circle onto cardboard using a round object. A plate or bowl works well. Make sure it is at least two to three inches wider than your oatmeal container. Trace a smaller circle in the center using your oatmeal container. This will form a ring.
Cut out your ring and slip it over the top of the container so it rests on the ridge of the oatmeal container. Glue your brim in place.
Use glue to cover your oatmeal container with green construction paper.
Have the children decorate their hats with glitter glue, markers and stickers. They can also cut a belt and other shapes out of construction paper and glue them onto their hats.