I received this tip from Rick of Ricks Detector's..........................49er@thegrid.net

Hi, a quick intro first. I built  my first detector from a Radio Shack kit some 30+ years ago with my Dad. It would detect a penny at  about 3 to 4 inches max.  Over the years since, my favorite
detectors included a Compass Yukon 77B, Garret ads Deep seeker, various Fisher
detectors and currently now for the last four years, the Sovereign and Excalibur. I primarily hunt at ocean, bay and lake swimming sites with scuba, elec. hookah, or wading gear. If conditions aren't  great I'll concentrate on my favorite rocky wet zones for digging and sniping on bedrock for
silver coins and jewelry. This will include lots of  boulder flipping. Since this is such an all consuming hobby of mine, just ask my wife, I became a Minelab and Sun ray dealer, which allows me to keep abreast of the latest technology and share this hobby with my friends. Many of them
are now diehard Sovereign users. I've also gotten into cache and treasure hunting with  others of the same bent with forays into mainland Mexico and several of our western states.  Anyway, here's a few tips that I use in the field that are worth mentioning:

 1.  The "bottomless bucket tool"-- Take a plastic five gallon paint bucket, cut the bottom out and reinforce the bottom cut edge with a 1 inch wide stainless  steel band riveted in place with flush rivets. At your favorite wet zone, when  the sand is like sponge and constantly caves on your target digs and your scoop won't pull  it out, use the bucket. Firmly press the bucket down, centered over the target zone, until you stop on a  rock or gravel layer or the rim is flush with the
surrounding sand. Quickly scoop out wet, mushy sand with your favorite home built scoop, I use a cut 1 gal. Clorox jug with handle intact for mine. In about 20 seconds you will have a 2 foot hole in
wet sand that won't cave in, even when an occasional small wave wash spills through the area. This is now usually deep enough to get at the ring or coin no matter how mushy the surrounding sand is. I've used this to also sample bedrock potholes for concentrated targets where the overburden is 1 to 2 ft thick. When conditions are right, you can find pockets with hundreds of coins, retrieve them all without  fighting the quicksand that normally floods that  dig site.

2. Pothole  digs  for coins and rings in the wet zone: ( If you dredge for gold, this is like sniping or crevacing for nuggets on bedrock) Again, when  conditions are right, you can dig out deeper
pockets on the hardpan or bedrock  when the sand layer is thin or washed off from a large cut. Some of our rocky coves have had one side stripped of all sand from a south swell surge, combined with high tides, leaving  a single layer of rocks and boulders on the bedrock  from
the low tide zone up to the bottom of the cliff face of the cove. This distance can cover some 150 ft. or more. At low tide, you follow the rocky ravines and trench lines moving up onto the beach and working  your way up to the cliff. Rock clumps and clusters usually form on top of a pocket in the crevice or ravine making a  natural trap for coins and rings that settled out from the former sand layers above.  One cove had 8 ft. of sand removed down to the rock layer. On the following
weekend, we pulled 27 rings, including a diamond wedding set from various rocky pockets. Some of the pockets yielded 200 to 300 coins each and were only 2 ft. long and about  12" deep. I use a small 2 ft. pry bar to dislodge the wedged in rocks. Then I quickly shovel or scoop out and sift the contents with a small wood framed screen and pick out the coins. I metal detect the bottom
of the pocket last to locate coins hidden in cracks on edge and any possible  rings still lurking on the bottom. On  this weekend I also recovered over  100 silver coins from these same pockets. Within a  week, over 2 ft. of sand had returned, covering most of this site.

3.  Coaxing coins from an iron laden sand pile. -- With the Sovereign, scrub the surface slowly  centering over each null in discriminate. If the sound will chirp at all next to the iron object, it's
likely to be a  coin. Even though you can't  get the pitch to go up to the same height with each pass it's still a target worth investigating. Sometimes the iron is so thick that the coin will only give a
single burp like sound from the null area, but its still a clue that you should listen for. My personal experience:  A wet January 3 yrs ago, at  Laguna Beach, Calif., on the wooden boardwalk area adjacent to the main beach, construction crews had started a  700 ft. reconstruction project. In 50
ft. sections over the  next  6 weeks, all the lumber decking was repaired or replaced. Rusted bolts and washers were torched off by the hundreds, lumber removed, and sand was  shoveled out
from beneath  the deck walkway to get the moisture level  down about 3 ft . lower. A sand
pile soon accumulated on the beach paralleling the construction site. During summer months, this area is usually jammed with people sitting along the raised edge of the boardwalk , watching the
volleyball tournaments in front of them on the beach.  The local detectorists sampled the growing sand pile with their pulse machines but quickly gave up because of the abundant iron. I patiently worked the site for 22 nightly visits of two to three hours each time over the next month and a
half. I even raked down the pile in stages with a hoe that  I modified with a 24" wide aluminum  blade.  Total take was over 3,000 coins from that site, including 5 rings,  numerous pocket knives, a few bracelets, and several 5 gl. buckets of trash.  A few of the silver coins dated
back to the 1880's, but  most all of the others were clads.  Even so, it was enough to pay for another  new  detector. (Part if of the pile I ended up screening because I was getting 6 or 7 coins per shovel full)