If your iron is spitting out the rusty stuff, it may take more than one application of the vinegar.
I don't think it's just the water that causes the problem. Perhaps it's just corrosion inside the iron. (I've had a brand new iron spit out rust. Wonder if it was one that had been returned and put back in stock.) In my newest iron, I have used ONLY distilled water, and occasionally I will get a drop of that yellowy stuff. I haven't used vinegar yet.
I may try the Iron Out next time.
I won't worry about the warranty, bc I usually drop the dang thing (or it falls of the ironing board) before it reaches old age. :roll: