Hi all, I noticed a couple of weeks ago that the fretboard on my bass seemed dry, and a perhaps little rougher than I remember it. Not driftwood dry, but probably in need of TLC. I have never oiled it, but when I have cleaned the bass and strings I have usually wiped it over with one of those white microfibre sponges, and sometimes used a light guitar polish on it. Should I be oiling it, and if so what is a recommended oil?  The fretboard is made of  "Indian Rosewood", whatever that may b