Whatever floats your boat, or seems to work for ya.
Some warm water is fine, the issue is to remove the salts in the powder and that does the trick.
I suspect the power wash is just getting a bit more carbon out but that's really not much of an issue.
What I find is the heat is once soaked with warm water, a bit of solvent, then use WD40 to displace any moisture....it'll raise any water residue so you can remove it...oil will set on top of the residue water.
Then finish with Barricade.
A day later I've never seen a rust trace even if a bit sloppy about the clean up.