Rinse the inside of the PVC brush with water to remove any standing debris.
Sprinkle the bottle brush with powdered cleaner until it is completely covered.
Insert the bottle brush into the pipe and scrub. You will not damage the PVC pipe with the bottle brush--it can stand up to sanding and steel wool. Continue scrubbing until you've reached every area inside the PVC pipe.
Rinse the pipe with water until all the cleaner has been removed and the water runs completely clear.
Let the pipe air dry completely before using it.