If glaze drips off a piece during firing and sticks to the kiln shelf, it may need to be chiseled or drilled off of the shelf. In many cases, the drips and sharp edges can be sanded smooth and are unnoticeable on a final piece. In other cases the divot in the foot ring cannot be sanded out and leaves a small chip mark behind, even after grinding.

While still fully functional (and often not visible as they are most commonly on the bottom of the foot ring),  these pieces are typically sold as seconds.