If you are still interested, he uses: waterproof sandpaper # 240 → # 400 → # 800 → # 1000 → # 1500 → # 2000 →Metal polish liquid (Pikal Metal Polish/ピカール 金属磨き) → rubbing compound (Soft 99 Rubbing Compound/ラビングコンパウンド) → abrasive tooth paste (Lion ZACT). For the metal part, he uses rotary tools (ミニルーターin Japanese). You can find cheap one at Daiso.