Some techniques experts use to clean up oil spills include physical blocking, physically skimming oil off the surface, burning and using dispersants. The exact techniques depend on a number of factors, including type and quantity of oil, water temperature, and local geography.
Blocking the spill involves the use of devices called "booms." Booms physically block the further spread of oil, usually through floating plastic or absorbent barriers. Since oil is lighter than water it tends to stay on the surface, making floating barriers effective to impede spreading. Boats and other machines that remove oil from the water are called "skimmers." They often use booms and other devices to gather the oil before specialized machines skim it from the water.
Burning and the use of dispersants are more controversial among experts, since they do not remove the pollution represented by the oil, but rather change or disperse it. Burning is most effective with fresh oil and calm water and can remove the oil before it affects the local environment. Burning also releases a great deal of pollution into the air. Dispersants are chemicals that can distribute the oil more evenly throughout the water, which can help save marshes and other sensitive coastal wetlands but does nothing to actually remove the oil from the environment.