it's very hard on the edge of a 
pocket knife to clean nails. you should
use a wire brush. or better yet, keep
your nails out of the weather and they 
won't rust, negating the need for cleaning 
them. i usually use nails as needed
rust or not. a generous-sized box of 
nails can be purchased very reasonably
at most hardware stores and home 
improvement centers. if not properly
driven into place, nails will absolutely
poke your pigs in addition to any other
livestock you may have in an enclosure.
i am also the product of a mixed marriage.
my father had black hair, and my mother
had brown hair. i've never admitted 
this publicly.