OK...we know the original Colt 1851s had color case hardened frames, and everything else was blued. But, HOW were they blued? Were they rust blued? Furnace blued? Charcoal blued? Hot tank bluing hadn't come along yet, so I am curious how they did it in any quantity. Rust bluing/browning was used on most rifles and shotguns then, but it is not very practical for pistols, and rust bluing small parts is a pain in the neck.