Wow! serious question and I have no idea. But please post photos of before and after and let us know what you find out! This would be great information to have!
I'd use some type of automotive de-greaser and then I'd sand down to bare wood.
Degreaser will "spread" the mess..sand it away. Depending on how deep it has penetrated this may not be able to be fully removed, a dark stain could mask it.
I was thinking about sanding it. I'm also anticipating it to smell like automotive oil. Any way to remove that odor? I hope to bring this piece into my great room.
My goal is to paint it a shade of white. Would painting it with Kilz first eliminate the odor? Or is there a better way to approach the odor?
Maybe an oxygen bleach cleaner (not chlorine bleach) would work. You could test it out on a small section of one of the pieces of furniture. If you do have staining after you clean it, it probably would need a primer like Kilz.
painting over the oil could be tough...you might need to use hd primer
@Lilli H I am no expert, but things I would try; soak up with sand for a few days first; sit in the sun with lemon juice applied every so often; sanding. It would be helpful to see a pic of the furniture to see the impact of the stain. I just might add a bit of character to the finished piece. I think the lemon juice would help to deodorize as well as fade the spot. Thanks for posting the question, and please do keep us up to date.
I'd love to see a picture...painting it white will be a challenge...have you considered painting the base white and the top dark.. to disguise the stain?
Another option is to seal the stain "in" and then apply a new wood veneer.
Thanks everyone. All good advice. The piece is an antique Hoosier kitchen that sadly has been used to store barn tools and stuff--much of it greasy and dirty. I am getting it as part of an estate so there is sentimental value to it as its been in the family for a long time. We have not attempted to move it from its spot in the barn yet. For all I know it may fall apart. But if it doesn't, then I want to attempt to clean it up for my home. Someone glued old flooring on the work counter, but some of it is torn off and suffers from oil/grease and old glue. I may simply sand it down and not paint it depending on how it looks. I'm not opposed to having its "patina" exposed. I'm almost more afraid of the odor than anything. I don't have a picture of it to share at this point.
Gail, I never heard of the lemon juice idea on wood. Does it work??
Shellac is the "standard" for Sealing wood that may be contaminated with pitch and resin. It also does a pretty good job on sealing odors.
Bullseye is readily available "pre-mixed"
@Lilli H - I have used lemon juice and sunshine on a lot of products, but I must admit I haven't used it on wood. I believe it is nontoxic and hasn't harmed any of the surfaces I have used it on, and I don't think it would harm wood either. Perhaps @KMS Woodworks could shine some light on this thought.
Lemon juice is acidic and very "wet" both of those are not so great for wood. I have finished some wood, using simple waxes and oils.
I bought a piece of furniture that had big oil stains on it. I sanded it and it came out. I don't know if you want to do that but it worked for me.