you couldn't use a magnet on the outside to attract the bolt/stud and slide it up to where you can reach it?

Drive the car though the winter a few times in the rust belt. It will fall out on its own.

Oh snap! You might have something there. My grandmother had little ice skater figurines and she'd make them "skate" on a cookie sheet by moving a magnet underneath.

Just use some wax paper or something to protect the paint.

This. Better yet, put the magnet on a small toy or something with wheels so that it does not actualy contact the outside of the chassis.

Why cant you just use a flexible magnet?

a bolt or nut will never outsmart me. as far as they are concerned..............i am a god!