for you beginners getting into plastic you never ever want to shake a gallon of plastic if you have to pour it out into a different container and use a metal rod to mix when you put it in the microwave do not over mix it and if you are getting bubbles heat in a short period of time what's the time the bubbles will come to the top and and burst I will not get into different companies of plastics this is unfair to them I use a wide variety from different companies and they are all different one way or the other . So you'll have to decipher which is better for you by a small a quality from each manufacturer and try it out for your self.