crystallization
This is a technique commonly done by chemists to purify compounds. During crystallization, an impure,solid compound is dissolved with a hot solvent. In the container the impurities and the needed compound move freely. When the solution cools down, the solvent can cannot hold all the solutes. Each solute will form a crystal. Therefore each crystal is made of only one molecule. Once it cools down if will be placed in a cold bath to complete the crystallization.
