Hey, don't dis da 'burgh, my hometown. And if you aren't a Steelers fan yet, we WILL convert you.
I think the only way to avoid some chance of negative effects on soil is to dig those puppies out. I really do pretty well when armed with the right tools. A lot of stuff that I just can't do, I delegate to my husband. He'll work hard at it before he'd admit defeat.
Could you hire a big strong guy to try it? Maybe a college kid?
Karen