His YouTube videos detail everything involved with making the prop come to life. The first video covers sculpting the master in clay. The second the creation of a plaster mold and casting copies using liquid latex. The final video features paint, hair, and final surface finishing. The series as a whole is the most detailed gaff tutorial I've ever seen.
The one caveat I would add regards the use of ashes for dusting down the finished product. Wood ashes are alkaline and over time could react with the latex or fibers of the hair. I think colored grout powder is a better alternative.