This paper aims to document the conservation processes of a polychrome wooden coffin from Saqqara dating back to the late period. The exterior part of the coffin is decorated with a painted layer, while the interior part is covered with a layer of the black resin decorated with a depiction of Nut, the goddess of the sky. The coffin was in a bad state of preservation. It was covered with a thick layer of dust, loose fragments of the painted and gesso layers, moreover, some parts of these layers were lost. Several areas were missing from the foot area of the coffin lid. 2D illustrations and 3D modules were made to document the coffin. The conservation processes of the wooden coffin included mechanical and chemical cleaning, reattachment of the separated parts of the ground layer and painted layers, filling the edge of the painted layer, and consolidating the black resin layer. The materials used in these processes exhibited stability and high retrievability, as confirmed by multiple researchers. The conservation process included mechanical cleaning using soft brushes, chemical cleaning using ethyl alcohol and water for the painted layer and xylene and water for the black resin layer, stabilization of the separated gesso layer was performed using primal AC33, filling cracks of the gesso layers using glass microballoon with Paraloid B72, consolidating the painted layer was achieved using Klucel E and the black resin layer with Nano Paraloid B72.