Cereal, also known as cellulose, is used primarily as a filler and to increase the toughness of the green sand. In addition, it will aid in pulling pockets. Cereal or cellulose can be oat, wood, or corn additions to a green sand system. If you are experiencing veining or tearing in your castings, you can add cereal to your green sand system to help eliminate those casting defects. Cereal acts as a filler in between the sand grains. Once the metal is poured into the green sand mold, the silica sand expands. If there is insufficient space for the sand to expand, you will get casting defects. The cereal will act as a filler and burn out when the molten metal enters the mold, allowing the sand to expand and reducing casting defects.