My Commander was used pretty hard. It was my EDC for years running EMS so she was beat to sh!t. But man she paid for herself 10 x over. When I retired her to a comfy space on my knife shelf all of the orginal black was worn, scared and her edge was rounded from quick sharpinings. She deserved better.
So heres what I did,
I took her all the way down and washed and dried all her parts. Then I took my dremel tool and some heavy scotchbrite wheels and removed all of the remaining black from the blade, pivot and scale screws. After that I matched the liners together in a vice and used a set of snap-on needle files to cut additional knurls to enhance grip on the underside and pommel area.
I also cleaned up and resharpend the existing jimbing with my spyderco ceramic files. For the pivot and scale screws I kept progressing to finer and finer scotchbrite wheels "till they was purdy". The "blade" was a challange
apparently that DLC type coating must need one hell of a surface profile for proper adhesion because once she was down to bare steel I looked at her with a loupe and could see that the surface was really pitted from a heavy sandblasting so I started with 220 emery cloth and went to 1500 emery. It took alot of this on each side to even her up as the sides were not nearly as flat as they appear, near the thumb disk. For the top and edge grind I used the progressive scotchbrite wheels inbetween sanding the sides to keep them satin. Then I dremel buff'd with lapping compound then hand rubbed her with a Mil-Spec scotchbrite polishing pad then a hard metal polish follow'd by a precious metal polish then fitz. Reworked the cutting edge with a progression of DMT diamond files till I got her as close to original as I could. Topped her off with a new Emerson s/s skull clip which was satin, so I buffed that to a shine and called her reborn. A little more than you asked but hope it helps.