Removing old oil stains from finished hardwood

[Sibley]

Am pulling the 60 year old carpet out of parent's new house. It's gross. Bigger issue is the hardwood under it all.

It's old, petroleum based foam padding. In high traffic areas the padding of course took a beating. Under the padding is a layer of caked dirt (using a scraper to get it up), and that caked dirt is oily from the padding. Which means the floor has oil stains.

Aside from all the staining, the floor is in beautiful condition. I'm trying to figure out how to get the oil stains out, or at least greatly improved. My usual process is to scrub the floor with blue Dawn dishsoap, wiping up excess water as I go and changing the water frequently. This will get the dirt up. But I'm not sure how much it work on oil stains. I was googling and saw that maybe putting an absorbent powder down and to let it soak up the oil would help. Worth a try, but what would be the best option? Other ideas?

[ysette9]

Would TSP damage the wood? It is great at cutting through grease to prep surfaces for painting.

[Sibley]

I'm not sure if tsp would be ok or not. And I did find out what the finish is - linseed oil. Which I know nothing about! So I have to research that.

[nereo]

Linseed Oil is a penetrating oil, which means it soaks into the wood instead of forming a film on the surface. That’s note entirely a bad thing in this case.

Your best bet is to first get the wood as clean as you can using scrapers (for caked on dirt), a mild detergent used for wood (Bona is what I’ve used, but dilute dawn can work too). After drying sand down as much as you like (or not at all)… depends on the condition and how thorough you want to be.  You can rent a floor sander and spend half a day to strip down the top 1/16” or so, or just lightly sand out the worst areas with a block sander.  More sanding will always look better, but it’s a time/effort hitng

Finally - if the staining is still visible (and it likely will be even with a lot of sanding), you can wipe on a 50:50 mixture of linseed oil and turpentine all over the floor.  That does double-duty - it acts as a solvent to help remove the old linseed oil impregnated with decades of smushed in dirt, but it also will help the stain ‘blend in’ with the surrounding wood and make everything look more uniform.

Old wood floors are a wonderful fine.  Why did anyone ever lay carpet over those??

[Gone Fishing]

Old wood floors are a wonderful fine.  Why did anyone ever lay carpet over those??

The same reason they will be ripping out granite countertops a decade or two for now, proclaming how glad they are to get rid of those "ugly" things!


Linseed oil does penetrate but it also polymerizes into a finish.  I find the the smell offensive and it hangs around for months (at least with my experience with "boiled" oil).  Beware any rags, paper, etc soaked in linseed oil can produce enough heat to self ignite.  Be sure to dispose of them properly.

[Metalcat]

General Finishes has a Facebook group where there are a ton of professionals and even reps from the company who will answer basically any wood question you have.

It's my favourite resource for any questions about wood finishing/refinishing.

[Sibley]

I've been researching. Lots. Agreed, linseed oil isn't the worst finish to have. And the flooring that isn't stained is beautiful.

@nereo  Sanding isn't a good idea - the wood is pretty thin already. If I can improve the staining sufficiently, that would be better for me. Let a future owner worry about having to pull out the floors if they sand too far! As for why it had carpet, I'm not complaining too much. Two other rooms the floors are basically in perfect condition, if dirty (they didn't have the 60s carpet). I just wish they'd pulled this carpet 20 years ago.

I did a bunch of scraping up of the dirt earlier, there's a bit more but I got most of it, and swept it all up. That helped quite a bit actually. I think my plan of attack next is to scrub with dawn. The floors are filthy after being under carpet for decades, they need a good scrub. Once they're clean I will be able to see more of what I'm dealing with. (This is going to take a week or more - lots of area to clean.) If I'm lucky, the dishsoap will help with the staining, but even if it doesn't getting the dirt off is good. Right now the floors are gritty and I do not want to sit on them.

From there, I will consider TSP and spot cleaning. @ysette9 , good call there, it appears that TSP is relatively safe for wood. Given the care needed to use TSP, I don't want to use it on everything, just the stained areas. I may also see if a layer of baking soda rubbed in would help lift the stains too, I've seen that mentioned a few times. But I'll determine the exact plan once I get the floor clean.

I do think there's at least one area with urine damage. This room will have an area rug so I can hide a variety of problems. But this staining is too extensive to hide.

Some pics here (the scale is weird, I have no idea what I did). This is before I pulled the staples and did a bunch of scraping up of dirt, so it looks a little better now.
https://imgur.com/a/w0zjrp6

[Sibley]

General Finishes has a Facebook group where there are a ton of professionals and even reps from the company who will answer basically any wood question you have.

It's my favourite resource for any questions about wood finishing/refinishing.

Found it, thanks. Have posted a question to them.

Day one of cleaning has completed. The dining room and bedroom are both cleaned. Dawn is working very well to get the dirt off, and there is a noticeable color change along with lots of very dirty water going down the drain. The bedroom has oil staining as well, I thought it was all dirt but nope. Luckily that is planned to be carpeted.

Next is the hallway, and then into the living room. These are the worst areas for the oil staining, plus also the dirtiest.

[affordablehousing]

Just looked at the pics and god that's awful! Why not just sand the floor and do it the right way? The finish looks fine around the edges but you could just get it uniform if you did it all at once. I guess it depends on whether anyone will live in the house but for me it would be hands down renting a sander and getting to work, then you can update the baseboards too with nice clean trim.

[Sibley]

Just looked at the pics and god that's awful! Why not just sand the floor and do it the right way? The finish looks fine around the edges but you could just get it uniform if you did it all at once. I guess it depends on whether anyone will live in the house but for me it would be hands down renting a sander and getting to work, then you can update the baseboards too with nice clean trim.

You are more than welcome to come do that. You have 2 weeks, there's a kitchen being installed, the bathroom is out of commission for at least 2 days, you have to dodge unhelpful parents, oh and btw you work full time, are in busy season, have a very unhappy cat at home (who is also getting periodically injured by the parent's cat), are fighting a stress injury in your dominant hand, have been working flat out on this house for a full month (and counting), and there's no money available to hire someone to do the work. There's also 2 bedrooms, a hallway, and a dining room which currently match this floor so you should probably do those as well. But you should also check that you CAN sand it first, because the floor isn't very thick.

That's why I'm not sanding. I have until Monday to figure out if we're carpeting over the whole mess. I have TSP, will give that a try this weekend. I need to get over there tonight and work on scrubbing the floors.

[Sibley]

Well, parents went rogue (very inadequate PPE) and tried the TSP today. It didn't work.

Got a suggestion from the FB group to try mineral spirits. That's next.

[BudgetSlasher]

Well, parents went rogue (very inadequate PPE) and tried the TSP today. It didn't work.

Got a suggestion from the FB group to try mineral spirits. That's next.

There are alot of things that I might not normally suggest on a hardwood floor that has already been finished, but since the floor is already damaged and it seems you are comfortable with the option of putting carpet back down there are a couple additional things I would suggest investigating. I've used both of these prior on wood for projects prior to finishings ... so that is to say you might with to test them in an out of the way spot and even if one of them works it may require reapplying BLO to blend with the existing flooring. Even then there is no guarantee that it will match perfectly right away or even if it will eventually age to match/blend.

I have used oxalic acid to remove stains from wood, mostly rust or water. In general it returns wood to its original coloring (not sure how it will play with BLO, hence the test suggestion). I have found that woods that tend to age or age quickly like the green hue to some poplar this can hasten the aging process. In addition to all of the things already suggested this would be my number one thing to add.

There are two-part wood bleaches, heck even household bleach *would* work. That can remove stains. Again I do not know how they play with BLO, but the bigger problem is they tend to lighten the wood in addition to removing stains, so I doubt they would be a good idea for blending into an existing floor. Though since you are comfortable recarpeting, I suppose they are worth a last ditch test.

In either of the above treatments, I have always treated the whole piece or all of one type of wood in the piece with the chemical to ensure an even appearance ... in some cases I suspect it may have been unnecessary/out of an abundance of caution.

If you do need to redo the BLO I am a big fan of mixing it 50/50 with mineral spirits. IMO it makes it easier to spread and perhaps dry a little quicker ... perhaps the thinner consistency allows it to penetrate deeper. Personally I tend to do BLO in 3 coats 24 hours apart, the first coat often consists of multiple passes over the same area as raw wood will soak up alot of oil. If I want apply a harder finish on top I tend to wait 7 days and apply an oil based, not water based, poly on top (my go to is general finishes wiping poly in satin). My FIL swears by a 1:1:1 mixture of BLO:mineral spirits:oil based poly (he also swears by general finishes) as a single step step finish with multiple coats possible until the desired finish is achieved. If the existing floor does not have a poly finish I would omit the poly step/addition to the mixture in the touch up areas unless you want to simply wipe the new mixture across the entire floor.

Finally, mixing chemicals or their residues can sometimes have different or unexpected results. Personally I would trial different chemicals in different and small areas. At the very least I would do a good wipe down/rinse of the area in question between trailing different chemicals. 

[lthenderson]

Everything really depends on how bad the stains are, how widespread they are, etc. In general, once wood has a stain in it, nothing short of sanding below the layer is ever going to remove it. Wood is just too porous and there is no way to get down into all those pores to get the stain particles out. You may try a multitude of chemicals suggested above and I'm sure they will lessen parts of the stain, especially those closest to the surface and you may reach a point where it is not as noticeable to be satisfactory. I always think stained floors really have only two options. Lessen the stain and live with the charm or sand/replace the flooring and have it look like new again.

[Sibley]

Well, parents move date is set. 9/2.

Parents have also apparently decided to sand and refinish the floor. Good luck to them. I wash my hands of it, they can handle the floor. There is a limit to my patience and tolerance, and they have massively exceeded it. (Sounds harsh, but they could have burned down my house yesterday. I'm DONE.)