Whelp, I'm sure no knifemaker. I have put satin finishes on a few knives, as much as is possible given the handle was obviously in the way and you can't really get down into those tight transition areas.
Scotchbrite works ok... there are more colors than green, and the real Scotchbrite brand is probably better than a lot of the cheapies sold as scouring pads. Gray, maroon I remember, but not what grit they are. Scotchbrite would be fine for removing the black coating.
Then I'd switch to sandpaper. Seems like the wet/dry sandpaper did a cleaner job, more uniform grit it seems(?). Another idea for something "stiff" behind the paper... try using popsicle sticks or stop by a medical supply place and get a box of tongue depressors (unsterilized are cheaper).
I've wrapped the sandpaper around it, worked ok. Agree the pro's start at one angle, then switch to finer grit and another angle to make sure they got all the previous scratches out. If you are sure you want, say, 400 or 600 final, you can start and finish with same grit. I'd do like JDEEBLADE suggested and try 600 grit first and you may be "done".
If you go past 600 to 800, 1000, 1500, it'll get progressively closer to mirror. In fact, 2000 is all but a buffed mirrored finish with a very fine "matte"-ing of the surface. Quite nice, but shiny.
Wet/dry is often sold in autoparts stores in the Bondo section.
Be careful or you'll round over crisp grind line transition from a flat to the (e.g.) hollow, blurring that nice change of surface. Stay on one surface at a time. Do the hollow or flat ground area first, then come back and do the flats. And tape the very edge of the knife with something more than thin tape, else you risk a really nice stupid mark on your fingers.
