What You Do: 1  Cut the soap base into 1 inch cubes, about 1 cup's worth, and place them into the Pyrex measuring cup. 2  Take 10 or 20 petals and put a toothpick through the base of each one of them. You will use the toothpick as a handle so leave it in the petal. 3  Place the soap in the microwave and heat it for 30 second intervals.