This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
The substance known as "crocus," which is so exceedingly useful as a polishing medium for steel, etc., may be very generally obtained in the cinders produced from coal containing iron. It will be easily recognized by its rusty color, and should be collected and reduced to a powder for future use. Steel burnishers may be brought to a high state of polish with this substance by rubbing them upon a buff made of soldiers' belt or hard wood. After this operation, the burnisher should be rubbed on a second buff charged with jewelers' rouge.