Used Motor Oil On Wood Deck . Used motor oil can perfectly preserve the wood. Make sure this fits by entering your model number. Hot Rods Finishing a wood truck bed The H.A.M.B. from www.jalopyjournal.com Scrub surface with dawn dish soap, rinse well. Make sure you put it on when the sun is beaming down and the poors are open in the wood. It gives v good protection but ends must be soaked in oil for a long time to be effective.