Spills and overcooking can create flareups that burn the outside of your pans, often leaving a dark sooty mess. If a pan has enough burnt material on the outside, it can affect the thermal properties of the pan, distributing heat unevenly and causing burnt food. You can clean the outside of your pan using a combination of plain baking soda and water.
Combine 2 tbsp of baking soda and enough water to form a thick paste.
Spread the paste over the burnt surface of your pan, wrapping the entire pan in cling film, if necessary, to hold the baking soda to uneven surfaces.
Allow the baking soda to work on the pan for several hours; overnight is best, if possible.
Use a plastic scrubber or dish rag to scrub the baking soda off the bottom of the pan, and the burnt residue with it.
Clean the entire pan with a gentle dish soap and rinse thoroughly.
Avoid cooking with pans that have burnt exteriors. Cooking with them will only help to set in the burn and scorch marks, making them more difficult to clean.
Do not use this cleaning technique on the inside of pans unless prescribed by the manufacturer. While most pans can stand a baking soda cleaning on the interior, some surfaces will degrade because of it. Only use baking soda cleaning on the exterior.