For removing nibs in the finish use a nib file. Either a fine or a coarse file from Steck is good, my personal favorite is the metal plane from Konig. Don't apply pressure while using just allow the weight of the file to cut off the nibs. The paper bag trick works best with dust dried in the finish leaving a sandpaper feel. If you truly would like to rub the finish to a lower sheen than high gloss then Abralon pads on an orbital sander are by far the best way to go.