At Deadspin, Tom Scocca puts together a handy flow chart to determine whether fans who catch foul balls should keep those foul balls. It’s pretty much spot-on.
A Ramon Castro foul ball ricocheted off the second deck and right into my dad’s nachos during my family’s first game at Citi Field in 2009. There were no kids in the immediate vicinity, so we kept the ball. It’s in my old bedroom at my parents’ house now with a small nacho-cheese stain still visible. A few nachos were lost upon impact, but most of them were salvageable and subsequently consumed.