Since cast iron utensils are never really smooth and have rough or bumpy bottom surface. Due to their rough exteriors, they can easily cause scratches on the induction cooktop, especially if it is of glass material. Moreover, the induction process can also be disrupted because of the roughcast iron utensils. To prevent this problem, make sure that you smooth out the obvious bumps or rough patches at the bottom of the cast iron utensils. You can also opt for enamel cast iron cookware, which is a smoother version of the typical cast iron cookware, thereby preventing any scratches. The downside of enamel cast iron is that it doesn’t reach a high temperature that a normal cast iron pan can do easily. Also, make sure that you clean the cast iron pans and induction cooktops thoroughly as dirt can also cause scratches on the surface.