The best place to find jewelry, is at swimming beaches. Hands down. a) Cool waters shrink fingers, or b) people taking off their jewelry for "safe-keeping" before going in for a dip, c) people thrusting their hands in and out of the sand when making sand castles, d) people putting on slippery suntan lotion, and then frolicking about pitching balls, frisbees, etc... etc. e) and let's face it: digging in sand is easier....... doh!
The best turf spots are going to be athletic venues. Football, soccer, baseball. Anything the requires frolicking around, taking on and off gloves, setting your stuff around the sidelines for "safekeeping", etc.... (yes, people actually take off their watches, cell-phones, even rings, etc... and will sometimes put them wrapped in their coat or fanny sack, kept for safe-keeping along the sidelines or by the goal post, etc... while they play.
The worst spots in turf are any turf that is used for picnicking and BBQ'ing/eating. The reason is, that food and drink, by their VERY NATURE, are wrapped in aluminum. You know, people wrapping their sandwhiches in foil. Treats that come in foil packets. Drinks come in aluminum cans, etc.. And people sometimes pitch their cans into the BBQ pit fires, which then turns them into aluminum nuggets. So if you're looking for low conductor gold rings, avoid BBQ picnic table type sites.
Be aware that some athletic fields double in purposes. That is: they are used both as a general park purpose, and also athletics. Versus some athletic fields, which are more like a "stadium" in mindset, where ....... it's not really seen or used as a "park", per se.
If you're not near the ocean or any freshwater swimming beaches, another sand option is: sand volley-ball courts, and sand wrestle pits.
