Usually the mushrooms you buy at the store look like this: dirty
#1: Don't wash or rinse your mushrooms. Mushrooms are sponges so they just absorb that water. I can't tell you how many times I've had stuffed mushrooms that someone else made and they are sitting in big puddles. I couldn't resist once and I asked my friend if she had washed her mushrooms, and she said she had, and I told her how to prevent her mushroom puddles in the future. That makes me a bad guest huh? Yikes. Anyway, you want your mushrooms to absorb the flavor of whatever sauce you are adding them to, or absorb the flavor of the stuffing that they are being stuffed with, when you wash them they absorb water preventing them from absorbing more flavor.
#2: Instead of washing, peel your mushrooms. You can peel with your fingers or use a knife, I used a knife here so you can see it better. You remove the stem from the mushroom. Inside the mushroom there is extra rim of skin, you grab some, lift it up and peel. Repeat until the outside layer is all peeled off.
That's it! You now have beautiful mushrooms!!!!
Now, go peel yourself some mushrooms to stuff or even slice to make stuffed chicken marsala!!!