In my searches of half dollar rolls, I have even found a few 90% that I did not spot by looking at the edge. It was very tarnished and discolored, so it did not have that bright silver look I was expecting. I agree with the above post, look at the edge to get anything obvious, then go thru each one by one. I do this anyway, as I also pull out the 1974D halves to put under a magnafying glass to see if it is a double die.