I don't have near the experience that most of you have on this forum have.In my limited experience,hunting by swings in parks and schools are my favorite,most productive spots.Not necessarily just under the swing but out in the grass where someone would jump off and land.These places have been full of dimes.Next would be jungle gyms,bike racks and around trees.I find more nickels around older trees here than any other place.Two old schools,burned down in the 60's,have been my best places for old silver coins.Also yards of old homes/homesites.My least productive spots have been around park benches and old,old country schools(the one room variety).We don't have bark around our newer playground equipment,usually pea gravel.This isn't usually very good.The local detectorists head there first because the digging is easy.I almost forgot,concession stands at ballfields have been great for finding quarters.