I had a small frag of orange monti fall behind the rockwork. I didn't notice it for quite a while. When I found it, it was pure white. I put it under an overhang (shaded light) for a week or so and then moved it into full light on the sand for a while. Now it is midway up the tank. It is not as orange as the other sps but very close. Like cazoo said, it is a slow process that takes a month or two.
Vickie