Go to the scene where the crew is pouring Sabastian's facial mask on... They put a tube in his mouth so that he could breath. Now watch... at some point one of the crew touches the tube with the slime and it pours from it, yet in the next picture the tube is clean again with no sign of the slime...
also about the tube thing...didn't they have to cut nose and mouth and eye sockets? If they put the tube in the mouth, wouldn't there have already been a hole from where the tube was???