Many homeowners install plastic mailboxes for their durability and affordability. Metal mailboxes can rust and dent, and wooden mailboxes are prone to rotting, especially in damp or humid climates. Plastic mailboxes, while sturdy, can get dirty fairly quickly and sometimes attract mold or mildew. The grime can look especially bad if you have a light-colored mailbox. You can keep your plastic mailbox clean with common household products and a little elbow grease.
Mix a few drops of dish soap into a bowl of warm water. Wipe the grime off your mailbox with the solution and a sponge. Rinse the mailbox with plain water and dry with paper towels.
Remove bird droppings from the box with warm soapy water and a nylon scrubber. Again, just a few drops of dish soap will do. While wearing protective gloves, gently scrub the stains and rinse the area with plain water. Discard the scrubber after using it.
Remove mold and mildew by spraying the mailbox with distilled white vinegar. Gently scrub the entire box with a nylon scrubber or soft-bristled brush and rinse it with clean water. Prevent mold and mildew from returning by spraying a layer of vinegar on the outside of the mailbox and allowing it to air-dry.