How to Clean Aluminum Diamond Plate

Melody Dawn

Truck bumpers, mud flaps, tool bins and running boards are commonly made of diamond plate aluminum. This is that shiny, diamond-shape-studded tread surface. Diamond plate has many folds and edges that make cleaning it difficult.

The diamonds are tough and microscopically rough, so they will tear cleaning sponges and cause scrapes on fingers and knuckles. When the creases cake with dirt or brake dust, the entire vehicle can look dirty and unkempt. Weekly cleaning will keep your auto's diamond plate clean and easier to maintain.

  1. Pour phosphoric acid into a spray bottle. Purchase phosphoric acid at any auto parts store.

  2. Test the acid on an inconspicuous place on your diamond plate like on the underside of your running boards. Spray the acid on the underside and allow it to sit for about 15 minutes. Spray occasionally to keep the board wet. Lightly scrub the board with a coarse scrubbing sponge. Rinse the board. Repeat on the rest of the diamond plate if no damage is done.

  3. Spray the top side of the running boards and any other area that has diamond plate. Take care not to get the acid on your paint or rubber. Spray on the diamond plate only.

  4. Scrub all dirty areas and rinse clean after 15 to 30 minutes.

  5. Polish the diamond plate by applying a thin layer of all-metal polish. Apply to 1-to-2-foot sections at a time like you would apply car wax.

  6. Buff the area with a buffer and wool pad. Continue adding polish and buffing until the entire diamond plate is polished.