Hi Im new here, so I'm not sure if this has been answered in a different thread. ( Im sure it has but i cant find it). Anyways, I just got a Korin Togiharu virgin carbon steel Gyuto. I tried to force patina using regular yellow mustard. Worked ok but I'm trying to get the patina off to redo it. I have tried baking soda and a blue scotch-brite sponge. but nothings coming off. I am perplexed, Does the scrub pad have to be the green kind? I did notice in the package that the blue scrub pad is "Non-Scratching" Could that be the issue? Any help would be appreciated. Thanks in advance.