Blunt the point on a 16 penny nail and then cut it off at a length that will reside within the confines of the body portion of the mold. Decide on your plastic color and using a whole nail dip the point into that hot plastic twice, cool and remove that plastic sleeve you've made. Slip the sleeve over your OILED blunted nail head and lay it in the belly section with the point facing to the back, clamp and inject. When cooled use a needle to find the point of the nail inside and tickle it out. If you are adding eyes and cover dip, nothing more to do. If you want to seal the cavity without the cover dip just touch a dab of hot plastic to the hole made during nail removal.
The cavity, left un-sealed could hold a weight or even a small piece of alkaseltzer.
