You want to END UP at that more dense, golden layer.... just under the powdery stuff that looks like spring growth. To do that, I use a cabinet scraper, working into the rind and away from what was just exposed. This leaves no tiny nicks behind from the scraper because you're wiping them away as you work.
You can leave a little of of the powdery stuff that can be removed, or mostly removed, with 240 grit. And even after sanding, it's ok to leave some in any valleys/grooves because it's better to leave it there than scrape or sand into the power fibers at ALL while trying to get it all out... it doesn't hurt anything, won't lift, and it kinda looks cool after its finished, especially if some kind of dye is used.
Knodes can have the crusty lip removed and then sanded some, but going too far, like with the rind, raises the chances of lifting a splinter.