A small group of amateur archaeologists in Philadelphia are digging into the city’s past — by excavating ancient outhouses. Armed with shovels, roughly 15 “privy diggers” are exposing and exploring 300-year-old bathrooms buried beneath the city’s historic neighborhoods, searching for artifacts. Their finds include glass bottles, pottery shards, and household items owners tossed into privies as trash. Some pieces can fetch hundreds — even thousands — of dollars among collectors. For Philadelphia