Scratch filler putty is best for filling and levelling minor dent and scratches on the metal surface. Before applying, clean the surface for any rust, dust, oil etc. sand with 320 no. grit sandpaper. Apply thin coats of Apar Scratch filler putty with putty knife whereever is necessary with 15 to 20 minutes flash off between coats. Deep dents shall be filled in thin layers with an interval of 20 minutes for each thin coat and allow to dry . After thorough drying, wet sand with 320 no. grit sandpaper and apply Apar primer surfacer spray paint.