There are many ways to get it off but some will damge the metal, and it reallty depends what grade of Stanless it is.

I'm Mechanical engineer and come across this all the time in my job, but never with cooking appliancies.

try the other methods above, by all means, but a good way of getting rid is with distilled vinegar. Mix half water and half distilled Malt vinegar, and l;et sit over night, then use a sctochbright scouring pad to clean it up. Stainless has a better corrosion resistance to acid than stong caustics, but again it's all dependent on the grade of stainless, 304, 316, 318 grades all have different corrosion resistancies.

You can also use salt, with the scouring pad. the salt crystals act as an abrasion agent and the salt its self eats into the metal to help it clean.

Try this as it may help clean it up.