It may help to know the Magic Eraser is designed to compress and break down as it's used, like a pencil eraser. It can leave behind small pieces of residue, just as a pencil eraser does. How long the product lasts depends on how many times you use it and how rough the surfaces you use it on are. For best results, wet the pad with water before you use it. Then squeeze out excess water rather than wringing or twisting the pad. We always want to leave you feeling impressed, so we'd like to learn more about your experience and see how we can help. Please give us a call at (800) 248-1612.