Originally Posted by NatalieF

I did a test to see if the Crayola Ultra Washable markers would wash out or set if ironed. I took my test a bit to the extreme, in the sense that I marked darker than I usually would (went over each mark an extra time, so double the ink) and ironed longer than I usually would (I set the iron for a good 10 to 15 seconds on the marks without moving), and washed afterwards with just water and no soap. My iron was at it's hottest setting. The fabric is 100% cotton. I hope this helps others.

on the steam setting, it ran the ink a bit, but nothing horrible. The red and pink left a ghost of a mark which I pointed out with arrows as I'm not sure it will show up on the monitor. They probably would have come out had I used soap. Nonetheless I would probably steer away from those colors, to be on the safe side.