To clean an aluminum pot or pan, fill it with 1 quart of water, add 1 tablespoon cream of tartar or 1 tablespoon lemon juice, and simmer until the discoloration is gone. Scour the pot or pan with steel wool to remove burned-on food. To polish, use a paste of baking soda and water or liquid non-abrasive bathroom cleaner. To protect it from further discoloration, never clean with a dishwasher or soak it for long periods of time.
Alternatively, use white vinegar to break up mineral discoloration in aluminum pots and pans. Boil 2 cups of vinegar for five minutes, drain, and let cool before rinsing. Scour with steel wool if needed.
Use cream of tartar and vinegar together for tough baked-on stains. Mix equal parts into a paste and scrub or boil 1/2 cup of vinegar and 2 tablespoons of cream of tartar in 1 quart of water for at least 10 minutes to break up heavy buildup. Scrub when the solution cools; repeat if necessary.
Cream of tartar and vinegar are both acids that loosen food particles. Cream of tartar is the powdered form of potassium bitartrate, which has mild bleaching properties.
For the most stubborn stains, use a gently abrasive commercial product like Bar Keeper's Friend after soaking the pan for 10 minutes. Rinse the pans thoroughly after scrubbing, and wear gloves to avoid skin irritation.