I would like to add a little something on the practices of Ithaca Gun Comapany on "Restoring" case colors on a receiver.
I do not remember exactly where I found the information, but it comes from the factory instuction manuals to the workers in the repairs department. It stated that from time to time customers might send a gun in due to wearing of case colors. Their method of "restoring" or touching up these colors was by irregular application of a cold bluing solution with a Q-tip.
You don't much more "low heat" than that.
I did not see anything mentioned about torches though.
Not to beat a dead horse here and make this terrible thread go any longer then it has to, but I believe this "trick" is right out of Ithaca's 1970s, maybe even 80s, Warranty Repair Manuals. My parents gun shop was Ithaca warranty for years and I still have all the old manuals, they are great for reference today.
This method was developed mostly in response to Ithaca-Perazzi owners complaining about their tiger-striped cyanide case colors wearing thin from handling their guns on the clays fields. I cannot recall if the method required the use of a torch or not, but I want to say that it did because you needed to heat the action before applying the cold blue.
I have never actually seen the process done because it was a little before my time, but I can recall my oldest brother saying my Dad did not like the process because it almost always rusted after it was done because of the cold blue (even after re-lacquering over it) and it just looked like sh*t to begin with. In my opinion there is no good way to touch up case colors, bone charcoal or cyanide. The actions have to be properly cleaned, polished, annealed, and re-cased using the historically correct method that was used by the factory when the gun was first built.
