Thanks for your suggestions on chemicals and warnings against drum sanding. I went shopping Monday morning for chemicals, and in the meantime Mr. Weedy made faster passes on the floor with the sander to avoid heating up and globbing the shellac or whatever was on the floor. Results: Denatured alcohol did nothing. I tried wiping with a rag, scrubbing with steel wool, flooding a small area and letting it sit, all with no results. Guess it's not shellac. I then tried lacquer thinner. Scrubbing with a rag seemed to have an effect, so I did a fairly large area. Once it dried, however, there was minimal results, and less so on the unsanded wood than sanded. I tried it in one of the bedrooms that had a single sanding pass, and quit once I started feeling a little stomach cramping. :-) Yes, I had the windows open and a fan going. Sanding that didn't seem any different from the area I didn't apply the lacquer thinner. Didn't try the mineral spirits yet. In the meantime Mr. Weedy had sanded one of the bedrooms about 18 times with 60 grit (seemed to create more dust than 20 grit), and made headway. I took an orbital sander with 40 grit to the spots left behind (slightly deeper grooves/dents) and here's where we're at: Bottom left corner is where I hand sanded. Lowe's had no oxalic acid, but we've got some in our garage 100 miles away, so we'll work on the kitchen again later. Also, in the meantime, we used a belt sander on the mosaic inlay portions to get off the lippage, machine sanded over it to even out the belt sander marks, and then chipped away with a hand sander to get the residual off. This shows what our eventual goal is, but it'll be dozens of hours if we have to hand sand off this finish. I've done some more googling and may try citrus strip or Formby's furniture restorer to remove the finish. We've also got this area that had tile over it. The thinset seems to have bleached out the wood where it touched, but even aggressive hand sanding is having a tough time evening out all the discoloration. I'm still very open to additional suggestions to attack this. And I must say that I now know the answer to the question, "why would anyone cover up hardwood floors?" Anyone who asks has never personally refinished them. :-)

My 1934 old house had had a fire before I bought it. I was told to use terpentine and linseed oil mixture, it looked really beautiful..I sanded it first. Danish oil also looks beauriful on old wood. Stains? You just have to sand first, then use a stain darker than the original. Use a wood conditioner first, then hand stain the wood, trying to blend around the stain until the spot on the floor blends in better. Apply 2 coats of poly. Keep the room as dust free as possible. I still have a dark spot on my living room floor that was burned. Doesn't bother me, just reminds me that this old house has a story to tell.

Choosing the right flooring type isn't enough for your living condition. You will have to consider the types of cut: flat sawn, rift and quarter sawn, quarter sawn or live sawn. Quarter sawn and rift & quarter sawn will be best choices, because expansion and contraction is along the thickness of the wood. You will need climate control all year round. 70 degrees at 40 % relative humidity is where you want to be throughout the year. The use of a humidifier/dehumidifier will be needed year round. Although, engineered flooring is more stable than solid. Using the wrong wood specie in your living condition can run the risk of de-laminating with engineered wood. If, the top veneer is more or less stable than it's core and backing. You will experience de-laminating in extreme humidity swings. Take in account of what the engineered flooring is constructed of: mdf or plywood. The width of the flooring will account for how much expansion and contracting also. 2 1/4" strips are the most stable. As you go wider, expect to see more wider seasonal gaps. Proper acclimating is critical, should be performed with a moisture meter. For 2 1/4" strip flooring , sub-floor and flooring moisture should be within 4%. For all other widths 2% moisture differentiation is allowed or should not be exceeded. Don't forget proper expansion gaps, which is the thickness of your flooring, example: 3/4" thick = 3/4" gap. Sub-floor type and condition will affect the performance of wood floors. All this needs to be considered for the proper and successful performance of your wood floors.

I know low gloss is all the rage....but people have issues with oily paw prints showing up with matte polyurethane finishes. The Hardwax oil finishes have had issues with DOG DROOL turning gray/brown/staining. Personally I LOVE a light/natural coloured floor (like hickory or character grade white oak) that has lots of movement (no stain) in a satin or semi-gloss finish. A factory finish SOLID hardwood is a great option as the factory finishes are often made using aluminum Oxide or ceramic infused nanobeads = SUPER TOUGH finish (hard to scratch). The LIGHT/natural gold tones are VERY forgiving. The MODERATE gloss levels like satin and semi-gloss are VERY forgiving. The FACTORY FINISHES with either Aluminum Oxide or Ceramic infused polyurethane are VERY tough. So....simply ADD all those qualities together and you get this type of purchase: Solid prefinished (aka factory finished) natural hardwood (no stain) in a satin or semi-gloss (personal choice). That's what you are looking for. Have fun.