Silver War Nickels - 1942-45. They are pretty easy to spot because the mint mark sits is X-TRA large font size right above the dome of monticello on the back including the Phillidelphia mint; D, S and P. Every year I get a couple of them in change.
Over the years I've primarily hunted the yards of old homes and frequently find silver nickels (and the other nickels too). The trick is digging the low nickel signals and those just above. I've found the silver nickels read a little higher on the target ID meters. My old White's Eagle I was exceptional at finding old silver nickels.
I have to confess that it is easier to dig all the low and mid-conductor signals when in a private yard due to there being less trash than, for example, a public park.
Also, those of us that hunt with detectors that feature some sort of Audio target ID often have to fight the urge to cherry pick just the high conductors.
Rich (Utah)