Here's a somewhat more scientific experiment than the middle-school microwave test:
"Emory University researchers tested the durability of the marshmallow candy. One of the tests demonstrated how dissolvable they were in water, acetone, sodium hydroxide and sulfuric acid. Peeps stood strong against those chemical foes.
Then came phenol. After an hour in this protein-destroying chemical, toxic to even humans, the only thing left in the solution were the Peeps’ eyes." The peepers!