Phenol: chloroform extraction to clean up RNA ( e.g. to remove DNAse or DNAse Inactivation Reagent.) Based on phenol/chloroform protocol (http://cshprotocols.cshlp.org/content/2010/6/pdb.prot5438.full), ethanol precipitation protocol (http://cshprotocols.cshlp.org/content/2010/6/pdb.prot5440.full)