If you don't have any iron cleaner, you can try a used dryer sheet - not the foam rubber kind but the type that feels like interfacing (I use Snuggle). When your iron is warm (be careful it's not so hot that you burn yourself!), rub the soleplate with the used dryer sheet. Then I usually lay a paper towel over the edge of the ironing board and rub the iron on that to remove any residue.