Denailing—the forcible extraction of the fingernails or toenails—was a favorite method of medieval torture that retains its popularity in the 21st century. It is an efficient form of torture that in modern use causes no permanent physical injury.
In its simplest form, the torture is conducted by spread-eagling the prisoner to a tabletop and using a metal forceps or pliers—often heated red-hot—to individually grasp each nail in turn and tear it from the finger or toe. A crueler variant used in medieval Spain was performed by introducing a sharp wedge of wood or metal between the flesh and each nail and slowly hammering the wedge under the nail until it was torn free.
Medieval German witch-hunters practiced an enhanced torture of exceptional cruelty, using rough skewers of wood or bone dipped in boiling sulfur. A number of such skewers were slowly driven into the flesh under the prisoner's toenails. Alternately, the skewer was dipped in boiling oil, which served a dual purpose of both burning the incredibly sensitive flesh and lubricating the needle so that the torturer could freely explore a wide surface area beneath the toenail. When enough skewers had been driven home to pry each nail loose from its bed, the nail was torn out at the root with a pair of pliers.