Mushrooms should be handled as little as possible. Leave in the paper bag or punnet from purchase and put this inside a polythene bag. Store in a cool place or the salad drawer of the refrigerator. Fresh buttons and cups should keep this way for 5-6 days, with opens and flats for 2-3 days. It is not necessary to peel cultivated mushrooms, simply trim off the tip of the stalk and wipe with a damp cloth. Rinse large quantities in a colander under running water and dry quickly. Do not leave mushrooms to soak. Because of their high water content mushrooms do not freeze very satisfactorily in their raw state, but can be open frozen very quickly to store for up to 2 months in a rigid container. It is better to sauté them in melted butter for 1-2 minutes, cool and store in small containers. Buttons: These are small, white and tightly closed, ideal to use both raw and cooked. Cups: The buttons grow slightly larger and more mature but are still closed underneath. Use for all cooking. Open Cups: When the fine skin breaks away, revealing the pinkish gills but the mushroom is still cup shaped, it is called an open cup. Opens and Flats: Fully-matured mushrooms whose gills have turned from light to dark brown. These have the best flavour and are ideal for frying, grilling and baking.