Drench a paper towel in vinegar and lay the iron on it for a good five minutes, then start rubbing again, more and more crud will come off. Now place the baking soda on the drenched paper towel, place the iron on top of it and start ironing.
Great ideas on how to make your little ones a cleaning kit and get them involved with the chores early on. If you start them young and convince them cleaning is fun, it will pay huge dividends in the future! Finally great cleaning ideas for kids :)