This is a topic of debate, with many people claiming that washing mushrooms causes them to become slimy and lose their flavour. The Mushroom Bureau advises cleaning mushrooms using a damp cloth. However, others argue that the amount of water they absorb is minimal as is the impact on taste. Mushrooms often have dirt on them so need to be washed, a wipe with a damp cloth or kitchen paper or a quick rinse is fine. If you decide to rinse make sure you dry them before you cook them, so they do not add additional moisture to your dish.