The detecting community for the most part has moved away from the simple beeper to target id machines. In many cases the only types of detecting areas available to us are heavily trashed and while "dig everything" will work for rural folks it just won't cut it in the cities. What is needed is a criteria to determine when to dig targets that show up as pulltabs or zinc pennies and when to ignore them. There is also I think a priority of items to dig, for instance when you stumble onto a undisturbed site that is rich with coins and perhaps jewelry also what do you do start digging pulltab signals just because gold rings appear as pulltabs or do you start with the coins?
Recently I found a site just like that, acres of prime hunting loaded with all kinds of targets. Properly detected I will work the site for several months taking layer after layer of objects away but I am concerned that my treasure site may be stripped by someone with a detector who just lucked upon it like I did. When I scan a site for the first time I look for large coins. If it is truly undisturbed there will be lots of quarters scattered all over the area. If the quarters are scarce then I may think that the site has been hunted before but when I have more time I will come back and work it. If there are very few coins then I will assume that it has probably hunted out and I may skip it.
Using that logic then I should take the coins first, especially the large coins and when someone drives up with a detector they will think that nothing is there giving me the time to extract the jewelry at my leisure!
When there is such a large area where folks have been discarding pulltabs the decision is a practical one. Select the areas that you will dig junk signals very carefully to limit your time digging junk. For instance in the football field there are lots of pulltabs all around the field but few in the center of it. The areas where it is most likely for someone to throw off a ring will be inside the field about 10 feet and where the heavy action took place which may be best about 20 to 30 yards from each goal posts. It is interesting to note that I found a ring on the 30 yard line on either end and away from the sidelines by at least 10 feet and also I found a ring in the middle which was dropped by someone in the band. I will go back soon to remove ALL targets that may be gold rings which may show up from nickle (for 10K gold) to penny (for large class rings) but I will maximize my hunting to provide me with the best chance for success and less hard work.
If I am in a ballpark outfield which may be very large and I am looking for jewelry then I must decide what, when, and where that I will dig. As I sweep my coil near the best areas I expect to have no more than one signal for every 3 or 4 steps but if I am getting 10 or more signals in such a large field in just 3 steps then I may just look for coins if I don't want to spend the day on my knees and just leave the jewelry for someone else. This philosophy means that my time hunting will be quality time without getting frustrated with detecting but making the very most out of what I have.
