White Sponge Smothering Corals

[revance]

I just noticed last night when my frogspawn was closed up that there is a white sponge growing all over it. The frogspawn has not been opening up fully lately and I wonder if this is why. I have never seen this kind of sponge before, it looks a lot like the yellow ones that are pretty common but it is completely white. It looks like pictures I have seen of clathrina sponges.

What is the best way to go about removing this? Can I just use a razor to cut it all off? Any precautions I should take to prevent it from releasing something nasty into the tank?