Ok, this is an old thread, but mine is an OLD Mirolin sink. It's probably close to 20 years old, so be careful, they might not even be using the same formula for the newer synthetic sink.
I tried everthing, including striaight bleach, scrubbing and mild abrasives with only limited success. By chance I used Scrubbing Bubbles bathroom cleanser and it did wonders. I don't really understand what chemical combination did the job so easily, because one of the main ingredients is chlorine bleach which didn't work well even when using it straight.
georgex
March 2013