Coffin nails are believed to be powerful in the tradition of hoodoo magic because the dead are seen as powerful and able to help intervene in magical spells -- this is based on African spiritual practices where one's ancestors are seen as being able to intervene with the gods on your behalf. Now, of course, virtually nobody selling coffin nails is really selling nails salvaged from a used coffin (and if anyone is, you're sure not going to be paying $3 for a set of nine.) In the photo above is a set of genuine from-an-old-coffin nails I acquired out of sheer luck (the leftmost); to the right are some quality replacements made by myself (top) and by the famous Karma Zain (bottom.) Typically, if you buy so-called coffin nails from a large hoodoo/occult supplier, all you're getting is a set of rusty nails. Smaller retailers sometimes make replacements using more elaborate methods. Indeed, since most commonly available things sold as coffin nails are not really nails ...
Folklore, magic, facts and fiction from Talia Felix and hoodoo-online.com where those who need magic can DO MAGIC.