Image via WikipediaMushrooms can be bought prepackaged, they are far less expensive if you buy them loose and fill your own bag. The only problem with that is some varieties in particular are covered with traces of peat from the growing medium they were formally in. It is not recommended that you ever wash mushrooms, so buy a blush or bronzer brush from the make up department and use to clean off individual mushrooms instead. The soft bristles are gentle to the tender mushrooms, yet highly effective at removing debris. Just thought you'd want to know.