HELP ! (cross post from flooring)

The floor guys spilled some rust colored acid wash on our cream/grey terrazzo floors which were in the process of being restored. Now, when you walk in the front door, you see about 8 quarter sized drops of a very dark rusty colored stain. Does anyone know of anyway to get it out ?

It happened recently, and they are the ones who had just pulled the tile and repaired and refinished the original terrazzo floors. But, as they left it with the stains, and did a pretty lousy job on some of the refinishing (not to mention put several holes in the walls) I can't say I have too much confidence in them.

Thanks in advance.