This recipe is taken from a wonderful book that no budding make up artist should be without "The Technique of the Professional Make-Up Artist" by Vincent JR Kehoe

20 grams of Gelatin powder (I like Knox unflavored the best)

12 cc of distilled water

100cc of glycerin

Place and stir items in bowl. Let sit for 45 minutes. Then put into double boiler(or one pot with water in it and another on top, with gelatin mixture inside.) and heat on low till the granules are dissolved. Then color with food coloring or halloween face paints. You can make softer items by decreasing the gelatin to 15 grams or harder by increasing to 25 grams. To use in mold, use a pressure mold and grease with petroleum jelly. Let cool and remove.