I use to find some really nice pieces in tot lots, but most of the tot lots around here have gone to the newer rubber matting which makes losing stuff much harder. However, if the tot lots in your area are still sand, wood chips, dirt or grass, or even pea gravel, try concentrating your efforts a few feet further away from the attractions, i.e., instead of hunting under the swings hunt where parents would stand while pushing thier children on the swings. Same goes for those spin-around type attractions, (forget what you call them) parents pushing on these things can toss a ring several feet away. I've watched a lot of other MDer's hunting tot lots and it always seems they hunt them in a big hurry and also right next to, or under, the attraction. Try to imagine where adults will usually stand and where a ring might go as it slips off an active hand.