I couldn't really tell how deep the etching is on Peter's blade but I have blued the whole face and used plain paper rolled tightly on a dowel to "sand" off the resisted high parts. It's a tricky business and not for the faint of heart but I have saved an etching or two that way. Mostly.they were ruined anyway (In my ignorance I sanded one removing spots and removed all the dark part) so I had little to lose.:shrug: