40% Silver Halves

What year? Are you talking Kenndys only? If they're 40% silvers, melt value would be $1.62 per, based on current copper and silver prices, but that's if they are total junk. Even AU would run around $2.20 to $2.40 each, from what I've seen. Or, you could go the route of ebay and charge five to seven times face value for them!

If they're all 1964 melt value is $3.91. Or, again, the ebay route would dictate you charge at LEAST 10X face value. So it depends on how much do you like your uncle!

Just curious, what are the years for the 40% halves? 1964 is the only year of the 90%, correct?

And for all practical purposes, 1970 is not included with other 40% halves since it was only included in Mint Sets and is the key for the series(not counting the special matte finish coins).

There are both Cu-Ni clad and 40% silver clad 1976-S half dollars. The 40% silver ones were made in both uncirculated and proof versions. The Cu-Ni clad are proof only. Any of the three varieties are potentially found in a roll, like any other NIFC coin.