There is one particular park where I like to detect but it is infested with everything. Old ring pulls, new ring pulls, tabs, (they all give different sounds in the gold range!!! nails, aluminum can slaw, old rusty nuts and bolts, buried sprinklers heads that will give you a sweet sounding solid 39!. You think you have silver but after you dig a 4-5inch hole, there it is, another *!#%! buried sprinkler head!!! Anyway, all I can do is put on the smallest coil (6inch Excellerator) and what I do is tilt the coil at a 45 degree angle and approach the target at different angles. Andy Sabich mentioned this effective method a long time ago and I have adopted this tip. It works to narrow and single out the spot where a GOOD sounding target is if there is a lot of junk around that particular good target and is wanting to null your metal detector out. There is no 100% surefire method and it's all about what works for the individual.