To remove aluminum oxidation from pots and pans, wash the piece of cookware to get rid of any dust, burnt pieces of food and grease. Boil the pan in a large heatproof container filled with a solution of acid, such as vinegar, cream of tartar or lemon juice. Don't use harsh abrasives such as steel wool, as they may scratch the surface.
Clean the piece thoroughly, including the edges and outer surfaces, before boiling it in acid, as dirt and grease prevent oxidation from dissolving in acid. To get rid of burnt food, boil some water in the pan for several minutes to soften the food, and scrape it off. When making an acid solution, use 2 tablespoons of a product that contains acid for each quart of water. Allow the piece to remain in boiling acid solution for at least 15 minutes.
If the piece isn't completely clean after this, complete the process again; it may take several tries to get rid of all the oxidation. Use half a lemon dipped in salt or some lemon juice and salt on a cloth to clean difficult spots. However, avoid rubbing the surface too hard, as salt can scratch it, too.