Place the pot or pan onto the stovetop burner.
Pour enough vinegar into it to cover the bottom of the pan. Add an equal amount of water and 2 tablespoons of baking soda to the vinegar
Turn on the burner and allow the solution to boil in the pan for 20 minutes.
Pour out the liquid and scrub any stubborn marks using a mesh dish cloth and baking soda.
Rinse the baking soda out of the pot or pan thoroughly.
Cover the marks on the pot or pan with a generous amount of baking soda.
Add enough water to the baking soda to form a paste on the surface. Allow it to saturate the stain for four or more hours.
Rinse the paste away.