I would start in all metal to feel out the ground a lot of iron lot of trash,if not then i would stay in this mode to hear everything, most depth and if something is being masked by another object,iron ,can trash,you should be able to catch a bell tone.To much iron and trash i would switch to relic which leaves the iron out.If it were a contest and they buried the coins ,i would start in all metal and switch to coins because they were jested buried and you want to dig and move fast.Were the plow went through try to get in the middle swing peak down side and in the valley then back up the other side.A lot of times the coins from the plow get brought up to top and sides.If you hit a trash area in ground remember someone had to bring it there so swing the are don't run away from it. Look for spots were the family had picnics and gatherings and trees were the kids might play or someone might take a rest.Try to work from house outward most chance of dropped coins.dry creak beds and around post use to hide stuff there.research and see if any tornado's or really bad weather hit the are and which direction it took, and see if he rebuilt in different area.Hope this helps others on the forum have a lot they can tell you.Watch out for cow-pies.good luck good hunting.