There's a few threads on here talking about that same issue - seems to be worse on some carb bodies than others.
The Al/Zn material they're made out of seems to be prone to getting that white, chalky layer on them after exposure to the carb dip. Mine get it too, to varying degrees across the differnt carb bodies.
No "one-answer" as to how to remove or minimize it, but most here will simply wash the carbs throughly with soap & water after dipping. Spray with carb spray cleaner as well. You really should blast compressed air through all those passages to make sure they're clean too.
The WD40 coating seems like a good way to slow the surfaces form oxidizing - shouldn't hurt anything, the gas will just wash it away.
Agree with hikermikem.
I don't have a compressor yet in the garage, but I do some computer work on the side, and had a few cans of air for dusting/cleaning, and it works in a pinch