Pinbacks are maybe the most mysterious realm of baseball collectibles. While some pins from the mid-20th century are extremely common to find, most aren't, and many are just about impossible to locate. Scarcity has nothing to do with talent — pins of Carl Hubbell, Mickey Mantle and Ted Williams are practically cheap, while those of Roy McMillan, Hank Thompson, Ned Garver and dozens of lesser players can sell for hundreds of dollars each.

My theory is that many of the tough pins from the 1950s in particular were basically salesman's samples. The tough pins more likely come from the Midwest rather than the Northeast — the vast majority of my PM-10s depict players from New York, Boston and Philadelphia teams.