If you notice rainbow-colored shimmering stains in your mixing bowl, these could be a consequence of using starchy foods and we recommend that you clean it in the following way:
Fill the mixing bowl with 6 cups / 1.5 liters of water and add a dishwasher tablet.
Then heat it all at 158°F / 70°C for 60 minutes on speed 3.
After that, pour away the cleaning solution and you can remove any remaining stains with a steel cleaner.
Then rinse the mixing bowl thoroughly with water and dry it.
Make sure that the cleaning solution does not come into contact with your eyes! And also do the cleaning out of the reach of children.