I had this happen on a hand embroidered pillow case I was making and the rust was on the white background. I took a new toothbrush and some bar soap and got as much as I could off. I finished the embroidery a couple of days later, put Shout on the spots, put it in a lingerie bag and washed it with my whites in cold water. The rust stain actually came out. I bought a new iron, threw that one away and decided to use a pressing cloth from that time forward! I have also starting using a spray bottle.