It may sound crazy but one of my hobbies is digging for antique bottles. Myself and my digging friends dig out old privies which sometimes contain really good old glass from the 19th century.
The old cities are the best places to dig but you have to go into the worst neighborhoods to find "spots". Over the years I have dug in some rough parts of Philadelphia, Newark NJ, Elizabeth, Trenton, New Brunswick etc. We have had guns pulled on us, bricks thrown at us and have had to deal with lots of bad people. I can tell you that Camden is definately a scary place, one of the worst that I ever dug in. It does have some nice old bottles though ;)
After you plant grass, mark the old privies so XRdsRev can dig up bottles...