Salmon has a yellow layer after cutting, that is, the protein of the fish, the burnt skin. In that case, it can only be washed off with that tool, and it can only be washed off with a special stain remover. Maybe this is what you're looking for, but that's not salmon. It's shad, which is actually not a kind of fish, but a synthetic product of herring with crab roe. There are red and yellow ones, and this depends on the color of the crabs used.