I've just bought a heavily used DB for dirt cheap, from the local school district, and the fingerboard is a bit grimy, has some shallow dings in it and has tape(?) on it marking the positions. Could I hit it with a medium grit (120) sandpaper and then go over it in a high grit (400) paper, and then refinish(?) it? I'm pretty new to DB, so sorry if this is totally obvious, or a repost!