Almost as appealing as the beautiful soaps themselves is how easily they can be made. To get started, you'll need clear glycerin soap, food coloring, coffee stirrers, a clean milk or juice carton (to use as a mold), and petroleum jelly. (You can also make multiple mini soaps by using ice-cube trays as your molds.) Glycerin is usually sold in large blocks at crafts stores; to melt it, cut it into small cubes that will fit in a microwavable bowl or measuring cup. Heat glycerin in a microwave on high, stirring at 15-second intervals, until it's completely melted. Mix liquid food coloring into bowl with a coffee stirrer. (Food coloring is very strong, so use it sparingly.) Coat the inside of the milk carton with petroleum jelly. Pour in melted glycerin. Let cool completely (about 2 hours).Tear away carton, and, using a bench scraper, slice block into individual bars.