We got it bad!! I can not find any help on getting rid of this. I have removed all my hardwood mulch and put down new pine bark mulch, and I am still getting the little tar like looking spots INSIDE MY GARAGE. I have talked to the County Agent and a so-called expert from Penn State and they say I know more about it than they do. I have white trim on my house and I own a white car. The county agent here in Delaware County Ohio said all he can suggest is that I Pray to get rid of it. So far that's not worked either.
My wife did find that the spots can be removed using Hydrigine Peroxide, but we can not find the source of the spots no matter how hard we look. There is nothing moist and rotten inside my garage, and we never open the windows since this has started. My next thing to do is sand and refinish the oak trim around the windows because that appears to be a possible source based on where we see the spots.