Set the iron on linen or your highest setting, no steam. fold a scrap piece of warm and natural batting into fourths and press with the iron. Keep turning the batting as you clean, this will give you 8 sides to wipe on to. Usually pull the iron across from heel to toe also helps to remove the scum. This method also worked when my GD decided to iron patch onto a garment before I came to help. Of course sticky side on iron plate....ugh...but all came clean with the warm and natural.