On a rosewood fingerboard, you can do this yourself by simply using a razor blade as a scraper. One or two passes along the fingerboard edge between the fret ends will do a long way. Then polish the entire edge lengthwise, frets ends and all, with sanding paper grades 360 through 800 and finally steel wool # 0000. Use foam rubber as backing for the sandpaper. Beware of any sharp fret ends. They must be filed down carefully, so you do not ruin the fingerboard before you start.
NB. Your warranty will most likely be ruined by this treatment.
Maple fingerboards may need some sort of refinish. If so, leave it to a pro.