No it really makes no difference but, if it makes you feel better make a semi strong solution of PBW and water ( assuming this is not a aluminum pot). Soak your kettle for a day or two and then take a scrubby pad like a scotch brite pad and scrub it should come off. I had something similar happen to my thermometer heat shield when I had a boil over and the method I described above took 95% of it all off.