The collected oil containers were drained, crushed, and used directly to make wood-plastic composites through reactive extrusion, using maleic anhydride (MA) and maleated polyethylene (PE-g-MA) as coupling agents. Oil residue in the container would be controlled at lower than 6 wt % through simple draining, and it played a role as a plasticizer in the plastics and composites. As a coupling agent, MA performed better than PE-g-MA. The comprehensive mechanical properties of oil container plastics (OCP)/wood/MA (60/40/2 w/w) composite were at the same level as those of neat plastic/wood/PE-g-MA 60/40/3.2 w/w) system. Both PE-g-MA and MA effectively improved water resistance of the OCP/wood flour composites, especially MA. The residual oil in the composites was stable under heat to about 200 degrees C or in the water, and it did not influence the thermal degradation behavior of the composites. The OCP was successfully used to make wood-plastic composite panels. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 964-972, 2011