They are made of Carborundum - a compound of silicon and carbon that is a product of nature and while there may be a whole lot of science in how they come to be, I just cared at how well my pans looked after using them. I just added hot water as directed and BOOM, clean pans with no chemicals or detergent and quick scrubbing. I moved on to the bottoms of my copper pans just to see if it would remove the marks from that and yup, it did!
These come with a money back guarantee so if you are looking for a no risk solution to cleaning your pots/pans or any other surface that has baked on goods (BBQ), go for it. You will be happy you did.