Your description reminds me of once searching a parking meter (just one parking meter among many) in a University town and in front of an apartment building (4 units per building). It was the end of winter, the ground was wet, the grass was not re-sprouting yet. I couldn't pin-point anything. Ever time I dug, out came a wheaty or nickle. I went about 1.5 hrs before dawn; and after 1.5 hrs I was still getting signals (from coins), though I had not moved even one foot away from that meter. My experience with the parking meter reminded me of Garrett's advice in the 1980s, which was "dig everything". For all the holes I put around that parking meter, it would have been just as easy for me to lay out a big cloth, cut several wide sections of grass (keep in mind this grass was stepped on galore because it was at curb parking), and then pull out fists of moist dirt and pick them apart for the mostly pennies that were probably 6-12" deep and every inch or so horizontally. When I was done, the grass was put back in place, tamped down with my foot, and the whole area looked "stepped on" as the rest of the curbside grass. Just before leaving I rechecked the area I searched, and I still couldn't pin-point because I had left maybe 20 coins still in that 12" x 12" section I had worked on for 1.5 hrs. Well, that is why we go back to certain places. If you think you have a good target, and if the grassy area seems to be well trodden (a good place to dig where you won't damage the landscape), get on your knees and start taking things out of the ground until you can find the goodie (or more) that is in there. Save all your trash so you can show any inquirers. The smaller coil is a great idea too, even for pinpointing trash in order to remove as much as you can. I pulled out a silver dollar once, near that location, that I was sure was an aluminum can (how the MD'r read it). You don't know what you will find until you dig it. If you are having problems, dig everything and surprise yourself with the "other things" you will find.