HOME SURFACE TREATMENTS QUALITY & ENVIRONMENT ABOUT US PLUG GALLERY Black oxidation Black oxidation (jettalization or bluing) is primarily a decorative surface treatment of steel. It gives a deep, blue-black color and is used on e.g. tool, machine and weapon details. The black oxidation Danod AB performs takes place in boiling lute salt at 140 degrees C. To obtain better protection against rust, the details are oiled. Smaller details are run in a drum and larger details are run as hammocks.