Ok heres what i did. Wash the blade, take an old sock (cotton ball would work but those are for my wifes makeup and my altoids tin so i didnt have extras) dab on blue in the pattern you want. in this case do not follow the instructions on the bottle, and let sit for a full 5 minutes (it may yellow) then drop in bleach. this creates poisonous gases so leave it out side. The longer you leave it in the deeper itll be. Each one of these was a different amount of time. The custom 20 minutes, the bk9 55 minutes, and the bk11 70 minutes.
When you take them out there will be a THICK coating of rust on em. scrape it off with a putty knife, then sand with 100 sandpaper, then 220. Then i reblue it to get the etchings darker, then sand again with 600 and up. i took it up to 1500. make sure to get all he rust off, it will hide in every crack and crevasse and it will continue to corrode if left on. Thanks for looking