How to remove material which stuck to iron when it was too hot.
O dear! Scrape it off with a steel wool soap pad, like Brillo or SOS, while the iron is cold. Then heat the iron, and iron some white paper towels until any residue is gone. If necessary, rub with the soap filled steel wool pad again. Once you have it cleaned, wash the surface with water and then iron some clean paper towel, again. Then iron some wax paper to put a nice glide back on your iron.
I've tried the brown paper trick and it didn't work - if your iron is teflon coated or stainless steel the SOS pads will scratch the finish. What I use is a scrubber sponge with the green scrub pads on the back of the sponge. Use warm water and soap, scrub with the green side until the debris is gone, rinse out the sponge then give the surface a swipe with the sponge side. You may have to do this with the iron set to a low heat level to help soften / loosen the debris depending on how bad it is.
set it really hot again and run it over a thick brown paper bag until the material is gone.