Fill your sink with hot water. Add several drops liquid dish soap and mix until the water is soapy.
Put the aluminum pot directly in the hot water and let it sit for several minutes.
Scrub the aluminum pot with a soft-bristled brush to remove the gray coating.
Rinse the pot completely. Continue if you can still see the gray coating.
Fill the pot with equal parts of water and white vinegar. Add 1 sliced lemon to the pot.
Boil the solution for 20 minutes. Add more of the solution if needed so the pot doesn’t run out of water.
Pour the solution down the drain. Rinse and dry the aluminum pot.