My ex-husband always told me you're supposed to peel the skin off mushrooms but everybody else I've spoken to says you're just supposed to brush the bits off them. There always still seems to be a little of the black stuff they grow in, I think it's peat. Is it Ok to just cook them with the skin still on if there's a little of the black stuff on the skin? If I wash them it just seems to make them too soggy.