I have also had good luck with a magic eraser (Mr. Clean makes one brand but there are others). I will say however my iron does not have a teflon sole plate so I can't attest to how well it would work or damage the teflon.
I made the mistake once of turning my new iron on before I had taken off the thin plastic sheet that protects the sole plate. Yikes!!! An internet search ensued and it said to get melted plastic off to put your iron in the freezer to harden the plastic and then it chips off. I had a full freezer so I sat it on a tray of ice cubes. It worked! I was able to chip almost all of the plastic off and the rest came off with the magic eraser. The dumb things we do sometimes....