by Lady of Mystery » Nov 19th, '14, 10:43
I've used nail nicks for years and have never been caught out with them, I've even gotten them past magicians before. The easiest way is to nick a corner of the billet as you pass it to your spec, a nicked corner is much more visible than an edge.
Like most things in magic, if you draw too much attention to something then there's a chance that you'll get caught out. I don't know what your routine is but with most billet routines, the spec shouldn't be paying too much attention to the billet itself. The billet should be insignificant, the important thing is the information that's inside.