Hey GG,
Well, to tell you the truth its about as easy to see as the oxygen outside the tank.
You won't see any external signs of this process, except perhaps through testing when the nitrate levels begin to drop on their own.
The yellow stuff can be vacuumed out safely. Any gelatenous white goop that forms on the rocks can be removed as well if it appears. Any algae and stuff that forms in the tank during the cycle can be removed as well. This is just another way of exporting the excess nutrients from the tank while the bacteria are growing.
Don't worry about depriving the bacteria of food, they will thrive one way or the other and by removing as much nutrients as possible you are only helping the cycle to progress faster. This is why I promote water changes throughout the cycle. As long as you add fish slowly, 1 at a time, after the cycle then you will be ok so far as the nitrifying bacteria are concerned.
Aaron
