I think an occasional blast from a baster is all that is needed.
After years I have found many neat critters appear on my rocks that scrubbing would or most likely have prevented never then from showing up...Many Sponges, Palys Zoas, Dusters and such.....
I would never think of scrubbing my rocks once the tank was established.
Here are a few shots from the past (taken over the years )of those pretty Sponges Cloves, Dusters and the such showing up in a spots not seeded or planted on.
Scrubbing would have prevented them "taking seed" ........Good Luck Reefing....Warren