Pounding the fiber further separates individual fibers.
Rinsing washes away non-fibrous material.
Here is your chance to really let your aggression out in a creative way. Put the cooked and rinsed fiber on a strong, flat surface that you don't mind getting dirty. Then, take your club, and pound away. Pound and fold, pound and fold. You'll see non-fibrous material draining out of the wet mass. You are making pulp. Be sure to wear old clothes for this step as they'll get splattered with glop.
When you feel that your pounding has accomplished as much as possible, or after at least 20 minutes of steady pounding (you'll get a workout), rinse the pulp very well in your big strainer. The picture at left shows me rinsing the fiber mid-way through the pounding process. I like to rinse the fiber a couple of times during this step. It gives me a break and lets me see how much I am accomplishing. Once a final rinse has been given, you are ready to proceed to step 5.