I have this, but isn't it way too thick and oily to even be absorped in a fretboard?
My ebony boards don't need much cleaning either, since the wood is so dense, but on an old HCGF advise, I bought this tiny bottle of Be a Fifer Fret Doctor oil (link:
https://beafifer.com/boredoctor.htm ) probably 15+ years ago and I still have half a bottle left. This stuff is especially magic on Rosewood boards and it's my go-to for my Burny Les Pauls.