I would try one of the color safe bleaches. I have found my iron spits when I get in a rush and don't let it get hot enough before trying to use it or it needs a good internal cleaning. I clean my iron by running white vinegar through it. I fill the reservoir with the vinegar and let it heat up really well. Then I turn the iron horizontally and let it steam away and push all the buttons (the spray and self-cleaning) multiple times. I have done this for years with no harm to any iron I have owned.