Green Sand Dollars?

When I unpacked some of the shells I brought back from Oregon I discovered that the sand dollar I had found had changed from a brownish color to a greenish color. After doing a little research, I discovered that brown sand dollars indicate that the sand dollar is still alive...whoops!!! I'm not sure about the greenish color, but it said on the internet to soak the sand dollar in fresh water and then possibly bleach it to bring back the white color. So, the sand dollar is now soaking and we'll see if the green goes away. At least it doesn't stink.