For ease of maintenance, you may find it easier to unmount your mailbox and perform these procedures at your workbench.
Begin by removing and cleaning the hinge pin. Scrape away any rust with a wire brush. Coat the hinge with WD-40 or other water-displacing lubricant spray and reassemble. Adjust hinge play per the owner's manual.
Wipe down the interior of the box with a damp rag and allow to fully dry. Tap the box body. It should resound to the blow. Boxes that respond with a dull thud should be replaced.
Inspect your mail pick-up flag for chipping or pitting, and touch up as necessary with red enamel paint. To prevent dripping, do not oversaturate the applicator.
Align your box post using a two-way post level. Remount the box. Add shims as necessary to level the box in the horizontal and vertical planes.
Add a sprig of rosemary or a potpourri sachet to the box to keep your mail smelling fresh.
Your box is ready to receive mail for another year!