Whatever machine you use, I set mine up with the lowest disc settings possible for the site. Generally, I set my machine in the low iron rejection settings--that way I'm not going to miss small bullets, cuff buttons, etc.. Also, I dig all "iffy" signals just in case my disc settings are still too high.
The reason for this is, once I was on a site where I was digging dropped CSA Gardners. I was using a Fisher 1266-X, and had my disc setting on 3.5, which was just BARELY enough to reject cut nails on my machine. I kept getting these "iffy" signals and dug one to find it was another dropped gardner.
Experimenting w/ my machine, I found that, because of mineralization, I had to drop my disc. to "2" to keep from rejecting the gardners.
If the site has light iron trash you might opt to hunt in all metal and just dig everything, or to dig all of the iron out that might be masking good stuff.
Also, keep in mind that w/ iron disc. you are also rejecting neat relics like gun parts, gun tools, eating utensils, and maybe even bayonets if you have your iron disc. too high.
But, if the site is completely covered up w/ small iron trash, you might opt to jack your discrimination up to investigate the site, THEN if you find there are goodies interspersed within the bad, decide if you want to dig out all of the masking iron, or cherry pick between the iron.
Which brings up another point: in trash infested sites, I personally think a DD coil can hunt between the trash better than a concentric coil. Also, you need a machine with quick response speed, for the same reason.
I knew a guy once who bragged that he never dug nails because of his disc. settings. I sure would like to hunt some of his old sites.
Secondly, if I'm hunting for a new site like a CW camp, I figure that there's probably going to be more iron in the site than lead or brass, so I hunt and listen accordingly. I start out hunting and listen for iron trash, not just good signals, and when I get in an area where I start hearing iron signals I slow way down, because some of the camps have a lot more nails and iron trash than good stuff. I start digging the iron signals to determine the age of the stuff in the ground, and if its old iron, I stay until I'm satisfied its not what I'm looking for before I move on.
Also, keep in mind that there are diligent relic hunters, and lazy ones. The lazy ones will walk through trashy areas without much scrutiny of what's in the ground. The diligent ones will stay in the iron and work it until they are satisfied with what it represents.
The CS era homestead is likely to be wall to wall metal, and not just stuff from the CW, but from the earliest habitation of the residence to the present. There are several different ways to approach such a site, but there are far, far more experienced people on this forum than I who I'll bet will tell you that they have homestead sites they have visited for years, w/ different detectors, and the sites still produce good stuff. Just remember that the cut nail or horseshoe you just rejected and decided not to dig could be masking something really good.
Also, don't take it from granted that the site is not worth bothering with if the land owner tells you its been hunted before, or you find evidence of earlier digging. Remember, there are such things as lazy relic hunters, and some people use inferior machines as well. The fact that someone has been there before you COULD mean that they actually dug some of the trash out of the way for you, OR, it could be proof that the site is actually worthwhile. And it could be that those earlier diggers had machines that just didn't see into the ground as deep as yours can.
Go slow. Be patient. Listen to every signal. Use the lowest Disc. possible.
Hope this helps.
