The focus on the photos is kind of soft, but I don't see any steam holes on the bottom of that iron, which might make it a little easier to clean without damaging. Try polishing the bottom with very fine sandpaper, like 600 grit or higher, or maybe #000 or #0000 steel wool. You may even want to go finer progressively abrasives, changng directions by 90 degrees each time you change abrasives, until the bottom is perfectly smooth and shiny, kind of like polishing the cast aluminum shell on a Kirby vacuum cleaner.