Shaggy mane mushrooms are an excellent edible wild mushroom, but you need to act quickly. The moment you spot them in the wild, make a plan, or pass them by. They need to be prepared or stored within 2-4 hours (preferably less) before they start to break down and spoil. Very quickly, these mushrooms will turn into a black, inky mess in your refrigerator. You must cook them right away or clean and freeze them.