Removing GSP from Live Rock

[Coralgurl]

I did search to see if a thread like this has been started, couldn't see anything, but if there is, please feel free to link up.

Anyway, my GSP has been growing nicely on the back wall of my tank, but its also spreading onto other rocks and I'd like to keep it isolated somewhat. I tried pulling it off but that was really ineffective. How do you get under the mat and remove it - the stuff is like in every nook and cranny of the rocks.

Thanks