Many methods of performing Perls Prussian blue stain for iron have been published, [2] Drury and Wallington (1980) give a protocol that uses a mixture of 1 part 2% hydrochloric acid and 1 part 2% potassium ferrocyanide that is applied to the section for 20–30 minutes followed by a rinse in distilled water and application of a counterstain such as eosin, safranin or neutral red.[5]