Try around large old trees. Esp in parks or recreation areas. In the old days and i guess this could still apply, people would picnic and gather under the shade of large trees. Many a coin has been lost under trees like this and often they were used as markers for people burying things that they did not want others to find but wanted to remember the location them selves. Alot of coin caches have been found at or near the base of large old trees. Just remember that the tree was smaller back 100 or 150 years ago but if its a large one it is worth a try. Dont overlook the ones back in the woods also cause you just never know what might be hidden there?