I have a customer wanting me to put top Soil back where I'm going to grind a bunch of stumps so they can get some grass growing pretty soon. What's a good top Soil to use? I've never bought any. But, I do have a massive pile of stump grinding shavings and dirt that I've brought to my house, it's been there for around 2 years I think. It's pretty black now, would it be good to use?