Does anyone know how to flush a power steering system?

I’ve removed the return hose, and had someone turn the wheel lock to lock while I turned the pump pulley. I repeated this until no more fluid came out of the return hose. I reattached the hose, filled the reservoir with clear/yellow fluid and repeated the above procedure until no air bubbles emerged.

The fluid in my reservoir is now reddish-pink. I’m sure that this is a result of some residual fluid mixing with my new clear fluid.

Is there a better way to purge the system of old fluid?

Thanks

Speedy