I've seen videos of someone dipping a wet finger into molten solder. The steam produced by the water vaporization protects the finger for the short, (very short!!), time it's in the solder.
Try it yourself with a soldering iron. I first saw a plumber do this with a large iron, heated with a blow torch. With a small iron tip, it's easy. Just be quick, make sure your finger is wet, and flick it fast enough that no hot solder sticks to the finger. Be careful where you flick it. The molten solder removed will burn bare skin.