Answer:
Iron
Step-by-step explanation:
Iron rich salts are under research in order to create ingredient of magnetic soap that can help clean up oil spills.
There were many other ingredients used before to remove oil spills but they are very costly and hazardous to environment. They can damage sea water and can disturb marine life.
The iron rich salts are used to creates soaps with metallic center. By this way when soap will be added to the water, the magnet will levitate iron rich bubble which can remove oil and dirt.