Or the other alternative: leave your fretboard alone. Seriously.
FWIW, I've used "Fret Dr" bore oil and it's fine, and darkens RW boards a bit, albeit temporarily. And compared to my guitars that have never had any oil treatment on them for yeeears (hmm, over 10yrs on one, coming on 25yrs on another), I see/feel zero difference. Read up on the "need" for oiling a fretboard ...it's dubious at best; damaging at worse when over applied; and this from experts whose business it is building guitars, not from the guys hawking their oil, let alone mere anecdotal web-testaments which you can take for what they're worth. In the final analysis, oiling a board serves little-if-any quantifiable benefits so long as the guitar is properly humidified. So if you do oil it, go very lightly, and then wait another decade!
Edward