Good info in this thread.
I have also noticed some woods just dont soak up oil. Or at least soak up very little. Olive is one and ziricote another that I've tried recently.
I use pure tung oil only. I try to mix it with 50% acetone or white spirit (a type of naphta) the first 3-4 coats.
But i have a feeling one can go more hardcore than that. basically different solvents dissolve different things. They have different polarity/dielectric constant and different dipole moment
https://en.wikipedia.org/wiki/Solvent#Physical_properties
I guess one could leach out the oils of the top layer of the wood before oiling it. I tried to leach oils with ethanol before gluing stuff and it seems to work somewhat. But I also have european brake cleaner (non chlorinated) and the wood looks very "dry" after brake clean..
Other solvents that one can find quite easily (here at least) seems to be "chemically pure gasoline" (I think this is actually heptane or hexane). The solvent you light barbecues with (think its similar to white spirit but much much cheaper). And diethyl ether (found in engine starter gas). Isopropyl alcohol. Some solvents seems to be kinda useless for oils like motor oils and greases. These will probably be almost useless for getting oil out of wood too i think.
I have found nothing as effective for removing grease/oil as brake clean with starting gas as the second best (but it evaporates
extremely fast).
These are not health products... wear carbon filter mask.
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There is one thing I have not tried on handles but on a lot of other wood stuff. 1 component clear polyurethane floor paint/finish.
Its cheap and it thins extremely well with acetone and white spirit. I'd guess the UV-stability will be very good. This is often used to paint boats here so its very durable.
its only nemesis seems to be leaving acetone puddles on it. it will remove it (it bubbles/flakes up) within about 2 -3 minutes. other than that its the perfect no maintainence finish for wood imo.
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I'm thinking: leaching out oils first with solvent of right polarity then maybe thinned polyurethane floor paint would be good for oily woods? As a durable solution.