I am not aware of the general opinions. The only thing I think is in about the middle of the purge shutting down and letting the stuff soak in the pump for a couple of hours or overnight might loosen up a lot more grunge.

Then run the remainder through. The injection pumps with rubber sealing rings in the delivery valves like the 603 I might avoid the soak though. For the 616 and 617 I see no harm doing this way.