I've posted this on GlobalIdeasBank.Org, but it's time for another reiteration. Buildings are constantly being torn down and the detritus often quickly hauled off by well-meaning but uninformed workers to the landfill transfer station. Sometimes they'll do the right thing and separate their trash from their clean wood, their steel from their plastic bags, but not often enough. There isn't much incentive from a contractor's POV to go through the hassle of separating that stuff out, they get paid for doing the work, not the hours of time that could be spent recycling. SO: Contractors should charge (and it should be understood) for recycling.
Be it further noted that when tearing down a big old building the contractor/demolition expert should be paid to put the site up on an official city registry for salvage. Then people could line up and sign up for a shot at taking away the stuff that might be reusable, big wooden beams, nice leaded glass windows, cool drawer pulls, hardwood floors in reasonable shape. It should be either rewarded or at least not penalized for contractors to re-use and recycle. It just makes sense.