You can leave your head on or off as pictured. If you would like your skeleton to be headless, you'll want to snap off the plastic head, add a little sticky wax to the bottom of it, and stick that on one of the skeleton's hands as you prepare your plastic piece for casting.
This project using the lost wax casting method, and also the same steps for a similar project for a sterling silver spider, also made from a plastic toy.
One important safety note, when making any kind of cast jewelry piece such as a charm or pendant, you will want to make sure you are not in the same room when you are burning out the plastic mold because the fumes are toxic.
After the piece is cast, file, polish, and clean it up. You'll notice the support pieces were left on the skeletons' body in the two pictured. It is a fairly fragile piece, so I decided to leave these on, but it's up to you when you finished getting him all ready. You can use wire to attach him to a jewelry finding, or solder on a jump ring before you finish polishing him up.
