J.F.
They actually sell stuff that cleans it. It comes in a little tube found in the iron aisle. You heat up your iron, put the cream on an old towel and rub the iron on the cream/towel in circular motions and the junk comes right off. If your iron is REALLY bad, buy two tubes. (read the directions before you use it, I was going off of memory and it may not be perfectly reliable!) :)