Not to worry about your new suit, any detergent worth its salt can remove blood stains. Today salt is inexpensive and universally available, but that wasn't always the case. Salt has been a valuable commodity in many cultures throughout history. Salt is sodium chloride. It can be obtained from mines or the oceans. Today salt is commonly mined from large deposits left by dried salt lakes. Modern mining and transportation methods have made salt an inexpensive commodity. Salt is an effective food preservative and before refrigeration was widely available, the demand for salt as a preservative was much greater. The human body requires salt for the regulation of fluid balance. Salt used as a seasoning adds to the taste of many foods. Because of salt's high value, it was used as a method of exchange. Roman soldiers received a salt allowance as part of their pay. In fact the word "salary" is derived from the Latin "salarium" meaning "of salt". To say that someone is "worth his salt" is to say they have earned their pay.