This is in reference to some discussions had on this thread.
http://parkerguns.org/forums/showthread.php?t=16043
Brian H's 34" DHE find.
Side discussion was in regards to removing bluing from a receiver and the possibility of case colors remaining underneath.
I have run a couple of test samples on an orphaned frame. I saw what both White Vinegar and Birchwood Casey Bluing remover did to case colors. Both of them removed the case colors from the water table of the frame I tested.
To properly get a decent bluing job, the surface must be polished. So case colors are gone. In the odd chance that a bluing job could be had with no polishing being done. The methods mentioned above to remove the bluing will also remove the colors underneath.