Here's a cool tip, a "hunted out park" will always have large trees, people in the past had picnics and leaned against these trees when they were small. Now that the tree is big all the coins that the people dropped in the past under the tree are now literally UNDER the tree. So if the park has recently knocked over or cut down an old tree and the stump has disintegrated you WILL find artifacts in the area the stump used to be. After Hurricane Sandy I found many coins and relics under the root systems of fallen trees in the city parks - some dating back as far as the late 19th century. So - moral of the story - an old park will always have treasure buried somewhere in it regardless if it was hunted to the hilt!