Magnetic Soap

Researchers from the University of Bristol have developed the Magnetic
Soap by dissolving iron in a range of inert surfactant materials
(composed of chloride and bromide) to create a substance that can be
controlled by magnets. The new soap is claimed "highly effective" in
cleaning up oil, and it can be easily removed after the "cleaning"
process so as to leave behind no potentially harmful chemicals in the
water.