I've hit home-sites dating to the 1850s, and walked away w/o a silver coin, even after multiple tries. Hard to imagine that the reason for this is that there were simply no silver coins lost there, in the last 150+ yrs, IF the home-site were continually used. I mean, one would THINK that ..... eventually ...... someone's gonna loose a coin, even if only a 1964 roosie
But the reason some sites that are even this old, might not be forthcoming with silver coins, is not because there simply aren't any there (although it's possible) but rather, that there is some prohibitive reason for them to be too difficult to find. Typcially it will be because the entire top layer of ground is utterly FILLED with trash or iron or both. Thus, the reason becomes, it's not worth the headache, so I usually leave for greener grounds (for example: places abandoned before 1900, which is before our modern "throw-away" age of aluminum, electrical, auto, etc... thus tending to be cleaner grounds).
Other reasons could be that a) the type soil/flora is either prohbitive jungle (can barely swing the coil anyplace), or the soil is moist enough that anything, is beyond your depth range b) someone already detected the place, and hammered the snot out of it, c) you're not skilled enough, and simply aren't getting the most out of your machine.
If the problem is due to masking of junk and iron, and since this site is your own property, there's nothing to stop you from "strip-mining" all the signals out of the most likely area. Ie.: even digging out the iron (in all metal mode), for instance, untill you are certain you have reached down to 8" or more. So like, if all you've dug is tabs, foil, clad, at 3" or less, and can't get a nail, or age indicator, or anything else deeper than that, then perhaps your detecting ability is what's the fault?
hard to say w/o being there.