Rosemary. Rosemary has a long history of being used to counteract bad spells and block their powers. Hand fresh or dried sprigs of rosemary in your home to dispel witchcraft and evil plots. Carry the leaves in a red cloth bag for protection. Season food with dried rosemary to improve your memory and increase your clarity. Rub the oil into yellow candles and light on Thursday to improve your study habits and grades.