a folder with carbon steel would be horrible for the simple fact that there are too many parts you can't get to, like the small section of the blade that the frame covers where it attaches. I don't know about you but when my folder gets dirty and I wash it off I don't take extra care not to get water between the blade and the frame, or down in the frame, or anywhere, I just let it all get soaked and then dry what I can, the rest dries itself, if it were carbon steel and I washed it the same way I would have to take it apart and dry/oil the entire blade to avoid rust, what a pain.