Place the pot under running so the water is running directly over the area with black residue.
Remove the pot from the water. Adjust it so that you can access the black residue. Often the residue is on the bottom of the pot.
Scrub the black residue on the stainless steel pot with a nylon-bristled brush. Do not use a metal-bristled brush.
Add just enough water to ½ cup baking soda to make a thick paste if the black residue is still visible. The paste should be the same consistency as toothpaste.
Rub the baking soda paste into the black residue with a clean cloth. The baking soda will act as a mild abrasive that will pick up the black residue. Remove the paste when it turns black and apply more paste until it no longer turns black.
Rinse the pot with clear water and dry it completely with a clean cloth.