It all depends on how efficient they are. The particular beach that I have been known to frequent has a machine called the "beach rake." The first time I visited this beach just over 7 years ago, I got there just as the beach rake was finishing up. I thought about when my buddy had told me about getting there before they cleaned the beach. I figured that I drove all the way down here and already put money in the parking meter, I'll give it a shot. Checking my log book I found $2.84 which included 7 quarters, 8 dimes, 1 nickel and 24 pennies. Most of the coins were found in the sand that was "raked". There was still plenty of trash that was missed by the rake not by me. If the rake missed the bigger trash like cans and bottles, I can't see it picking up small things like coins and jewelry. My buddy also mentioned something about magnets picking up metal on the beach. With as many bottle caps as I dig there is no way they are equipped with magnets. Every machine is different. Good Luck.