Diamond plate aluminum, usually found on trucks and in industrial kitchens, is prone to collecting dirt. When covered in water residue, mud, grease and scum, the diamond plate's texture makes dirt more unsightly than it would be on regular aluminum. Diamond plate is difficult to clean: It is rough on most cleaning cloths and can do a real number on your bare fingers. But with some phosphoric acid and polishing tools from your local auto store, you can restore your aluminum's original sparkle.
Use a clean funnel to fill the spray bottle with phosphoric acid. Wearing rubber or latex gloves to protect your hands.
Use duct tape to tape off the areas immediately surrounding the diamond plate. This helps prevent damage from the acid.
Wearing your gloves, spray the aluminum with the phosphoric acid. Keep the aluminum wet for 20 to 30 minutes, re-spraying the areas that dry and scrubbing the dirtiest and most damaged places with a nylon scrubbing sponge. The aluminum will turn white as the phosphoric acid works on it.
Rinse the diamond plate with cold water from your garden hose, or use a bucket of water and a large sponge.
Polish the diamond plate with an aluminum polish applied to a polishing block. Polish in the direction of the diamond plate's grooves.
Buff the aluminum to a shine with a clean terry cloth.
