Commodity money cans or foil pouches of mackerel fish fillets, which have a fairly standard cost and are easy to store. These may be exchanged for many services in prisons where personal possession of currency is prohibited. In situations where the commodity is metal, typically gold or silver, a government mint will often coin money by placing a mark on the metal that serves as a guarantee of the weight and purity of the metal. In doing so, the government will often impose a fee which is known as seigniorage. The role of a mint and of coin differs between commodity money
Purity and Danger contexts. What is regarded as dirt in a given society is any matter considered out of place. (Douglas took this lead from William James.) She attempted to clarify the differences between the sacred, the clean and the unclean in different societies and times. But this does not entail judging religions as pessimistic or optimistic in their understanding of purity or dirt—e.g., as dirt-affirming or otherwise. Through a complex and sophisticated reading of ritual, religion, and lifestyle, Douglas challenged Western ideas of pollution, making clear how the context and social history is essential. As an example of this approach, Douglas first