get some warm water and qtips and you will need to gently RUB the area, your basically going to get it wet, this is why I said, no need to let the wet paper towels touch it because you'll be keeping it wet. clean around, and on it. Hopefully you will not have to attempt this because again this is really risky.. I shake all the time when I need to do this. Scares the crap out of me and I've done it to quite a few of them.. LOL
The water can't be cold and you don't want it to hot, check it on your wrist. I'll tell you what is very surprising is her eyes are opened, NORMALLY a duck in this position will act as though they are dead, they sleep, sleep, sleep so this is a very very good sign that she's a fighter..
Now, you mentioned some goo stuff in her shell, what color was it? Green, yellow, red, did it look like a snot ball????