on rosewood fingerboards
what i do is i tape up the fingerboard with blue painters tape, then i use very fine steel woll and gibson low abraision metal cleaner. after the frets are clean i take off the tape and with a poilish cloth i take everclear (95% pure grain alcohol) and i use it to wipe all the oils off the finger board and the neck. the i take a soft tooth brush and use gibson fret board conditioner is small cricles until every fret is done. then i leave it sit for about 2 hours and start to "buff" everything with a second cloth.
on maple
i use orange clean. and spray it down lightly the 'buff' it all away with a soft cloth. if its way too dry afterwards ill take a peice of wax and rub it against the fingerboard then use a tack cloth the wax it to a high shine.
i might be wrong becauce the alcohol zaps all the moister out of the fingerboard, but after i apply the conditioner its smoth and beautiful again.
They say the END is near, but I'm Tired of waiting.