I can vouch for an example of potential nail reuse by burning of a
dilapidated structure and then collecting the nails.  On our farm in the
early 1960s, my parents moved a decrepit, formerly attached kitchen
(unused after house remodelling a decade earlier) to a fallow field,
burnt the structure and then collected the nails with old Model T Ford
magneto magnets.  However, I'm not sure if my father reused the nails or
if they were collected only to prevent tire punctures.

Larry Buhr
University of Nevada, Reno