Grille decontamination apparatus includes a frame, a drive transmission system, drive pulley, wheel bearing and enclosed rotary drag chain, tooth harrows and irons around its rotation. In the drive motor reducer, the rotary drag chain rotary movement from the bottom up, when the rake teeth on the operation of the traction chain axis to the positive side gridlines, rake teeth that is inserted into the gap in the irons for clearance from bottom to top fishing action, will the gridlines are trapped in the debris scraped off the rake. Since the tooth rake design double double tooth harrow teeth at an angle, so that when a tooth is inserted fishing clear gap in the irons, another tooth is bound to its solid debris surrounded the surrounds, without their lacuna formation, high removal efficiency and thorough. When (rain grille) to the machine running the upper tooth rake debris to fall off by gravity or transport container on board.