I have not tried the eraser, but will when I can get one brought into Brazil. It sounds a product knuts need to have.
In the mean time, I use #600 or #800 SiC grit with oil and a cloth applying light pressure. I have not noticed any damage to the finishes on any of the knives rust has been removed from using this method. Several folks I have spoke with use a fine grade of steel wool and oil.
BTW, has anyone else noticed that bead blast finishes tend to rust more easily than others? I have found this especially true with S30V.
Steve