POTS AND PANS • To Brighten Badly Discolored Aluminum: Gently boil any of the following: the peel of an apple; slices of grapefruit, lemon, orange, or tomato; or, during rhubarb season, some rhubarb stalks in the pot until the stains vanish. To clean the entire pot, be sure to fill it With as much water as possible.