On my Fraser style rifle, engraved by Roger Sampson, I did a light blast of 320 AO then waxed the metal. Regular oiling/waxing and time has filled the engraving giving it a beautifully black engraved lines on a wonderful grey surface. Never any corrosion issues or concerns and I have used mine on hunting trips. I wax it before I go and dry it good if it gets damp.