Pour equal parts of water and white vinegar in a large pan that the aluminum pot can sit in. This mixture removes hard-water stains.
To clean aluminum that is stained or discolored, stir 2 tablespoons of cream of tartar for every quart of water in a large pan until dissolved.
Set the aluminum pot in the larger pan so the bottom is covered with either the vinegar or the cream of tartar solution
Boil and simmer the mixture for approximately 10 minutes. Turn off the heat, and allow the pot to cool.
Wash the aluminum pot under hot running water, using dish detergent. Rinse it well to remove all the soap. Dry the aluminum pot inside and out with a soft towel to prevent water spots.