I've found about 10 '60s pennies in really good shape in the last week. I thought they were newish pennies until I flipped them over and saw the dates. The oldest one is 1961. These coins look like they were barely in circulation.
You know what, I was thinking the exact same thing yesterday! I was going thru my pocket change and saw a bright and shiny 1963 cent.
I don't know what part of the country you folks are from, but I traded 8 rolls at my local gas station (South Carolina by the way) Friday and got an AU 1962, 1964, 1966, & 1967. Each one was in a different roll. I also got an XF 1945 Wheatie. This is quite odd. I like it though!
Two things--either someone didn't need them and "salted" them back into circulation for someone to find (I've done that), or someone stole them and used them for change at a convenience store (my nephew did that--after breaking them out of the holders.) I have some heavily circulated Lincolns back to 1910 I'm planning to salt, in the hopes that some kid finds them.
I think a lot of it has to do with the financial situation. At 2 am when you're broke and out of cigarettes or beer you can't exactly take those old coins to the pawn shop or coin store so you just spend them at face value. That's my theory, anyway.