Every 3000 miles or every three months, a few drops of light oil or lock lubricant should be applied to the hinges and latch assemblies of the doors, 
Hood, and trunk or liftgate. Also, the door latch strikers ought to be greased over by a slim layer to reduce the amount of wear and enhance the working mechanism of the door. Of the two, the padlocks used for the door and trunk or lift gate should be coated with the spray-on graphite lubricant.