Bluing and parkerizing (Phosphate) are not very good at protecting the metal from rust and corrosion. They are intended to etch the surface of the metal so oil will adhere. Oil will not stick to polished steel so it rusts fairly easily. For pocket carry, stainless steel is better with hard chrome and satin (electroless) nickle coming in 2nd and 3rd
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"Robo is right" Fuzzball