If the stainless steel pot turn brown and violet the middle part of them bottom becomes blue, can it be use?

Its ugly but will still work. It has been overheated. Some of the resistance to stains/sticking may have been lost but it whould still be usable.





Stainles steel cleaner for welders may remove some of the discoloration (careful! contains phosphoric acid !) and scrub it well. Thoroughly rinse it and boil some water before using it for food to be on the safe side if you use the cleaner.





The color is from carbon precipitation.