hi. i have discovered a small tot lot which has swings and climbing frame which are situated on a rectangular sand pit within a grass park. the pit is 2ft deep. i have pulled out over 300 coins in the last 2 trips of 2hrs each. but no jewellery. i have xterra 305. am thinking of sieving it. i cant beleive there is so many coins sometimes 5 hits in a sweep, but no jewellery. any advice ?