I bought one when they first came on the market and tossed it under the kitchen sink (forgot I had it). My daughter discovered it (months later) and became very excited, telling me how wonderful that they are. After scrubbing my antique bathtub for hours with conventional cleaners, I remembered the Magic Eraser, and decided to see what the hype was. I was blown away. In less than 5 minutes, my bathtub was spotless and white!! I'm still stunned at how well these things work!!! I was also curious about the ingredients (tried to search it out on line). These are the best thing invented next to a toothbrush!!