I have an electric guitar, and its fingerboard in is rough shape after years of barely touching it and being lent to my younger brother (big mistake). I unfortunately don’t have an instrument shop close, so I would have to order oil for it, and even the closest one only carries like 1 or 2 kinds of string kits and a few arranger keyboards, not cleaning products.
While I probably could get mineral oil (not at the moment of writing this, due to weekends), I’m wondering how well cooking oil would work. Tried some grapeseed oil on some other piece of wood, where it wouldn’t be a problem.
NOTE: Likely will go with the mineral oil, so I also have something to clean strings with.


Linseed oil is a good choice because the oil will partially polymerizes as it oxidizes. Tung oil is also excellent. Most commercial products are a blend of these.
I recommend this also, but put a REALLY thin coat on. Like you should think you’ve barely got any on, and you should then wipe it off and think you’ve wiped too much off. There is a lot of bad advice out there about these oils. You can put more coats on if you think it needs it, 24 hours apart. If you put too much on, it will tend to look matte, or worse, get gummy.
Preach!
24h is not enough time to build coats, not for BLO and absolutely not for any natural oil.
You need to wait much longer, else you’re just saturating the wood more and more (which isn’t necessarily a bad thing).
The oils will take much longer to polymerize in the wood, you can prevent any spotting by wiping off any excess if it shows on the surface.
24 hr is enough if the coat is thin enough.
I don’t think that’s the case. I tested the drying time of different oils on a sheet of plastic in optimal conditions (summer, sunlight, next to an open window) and it still took 2-3 days for the first ones to dry (being tung oil and perilla oil, I think).
I don’t see how you could accomplish that on wood, unless you’re using drying agents, of course.
I have recently done this. Used tung oil and mixed in a bit of pigment to create sort of a transparent oil color for added saturation.
Worked well, but the oil takes multiple weeks to fully dry under best conditions until it doesn’t smell anymore.
I would either take the time and wait or use a boiled linseed oil finish with added drying agents.
Also, I had an old bass neck that was treated with the usual mineral oils before. Even though I had flooded the fretboard with naptha, beforehand, it got a bit messy. Oily spots and uneven soaking everywhere. Still not sure if it worked, so I guess it’s possibly one time mineral oil, always mineral oil.