Cool the burned or stained Calphalon pot completely, then place it in the freezer for two hours.
Remove the pot from the freezer and gently scrape off all frozen food and grease spots with the edge of a wooden spatula.
Pour 1 cup of white vinegar into the pot. Add 1 tablespoon of baking soda and enough water to completely cover the burn marks and stains. Stir the solution with the wooden spatula to mix in the baking soda.
Heat the solution to a boil, then turn off the heat and remove the pot from the stove. Leave the vinegar and baking soda solution in the pot until it's warm to the touch.
Scrub off the remaining burn marks with a nylon mesh sponge. Soak the sponge in the vinegar and baking soda solution and scrub off burn marks on the outside of the pot, as well.
Empty out the vinegar and baking soda solution. Place 2 to 3 drops of dishwashing detergent in the pot and fill it halfway with water, then wash the pot with this solution.
Rinse your Calphalon pot thoroughly with water and dry it with a clean kitchen towel.