Caution using a hot plate you can burn your plastic very easily the safest way to the plastic is the microwave. if you do use a hot plate put a barrier between the pan in the burner and gradually heat your plastic. you can go to the goodwill or a garage sale something like that and pick up a used microwave and go to Walmart or any place and pick up the Pyrex cups I use a commercial microwave and also I use a cheap one that commercial grade that I have is about 300 bucks but it is well worth the money because it takes a pounding and unable to do the right temperatures that I want we have one dial I turned on for about one minute at a time and keep stirring until I get it to where I want. at your coloring before you put sure plastic in the microwave. I don't do it this way but anyway that's way they usually do it.