In recent years there have been many oil tanker disasters, just like the one shown in Figure. These have resulted in millions of litres of oil being washed into the sea. Oil and water do not mix easily. They are said to be immiscible. When cleaning up disasters of this type, a range of chemicals can be added to the oil to make it more soluble. This results in oil and water mixing with each other. They are now said to be miscible. The following techniques can be used to separate mixtures of liquids.