Looks pretty good in this picture. Believe me, its dirty.

Here is a link that might be useful: floor

I ring my mop out till just damp.I use murphys oil soap smells good looks good

Just a plain wring out mop and water would be where I'd start. If you see that water soaking into the wood, then it's time for a refinish Bruce, Bona, and many other wood floor experts have products designed especially for wood floors, and that is what I would look for.

If it is finished with shellac or lacquer or even an oil finish, an oil soap won't damage the floor, but it should always be rinsed. It will cause dirt to be attracted to the floor. If it has a poly finish, oil soap should never be used. it will degrade the poly and cause you to have to do a complete sand down to the bare wood rather than a simple screen and recoat.

Vacuum it thoroughly if drywall dust is present.

Like a crevice tool in every joint of the floor.

You want to get as much drywall dust out before ANY water has a chance to turn it back into drywall mud that can then harden again especially if it was premixed joint compound in a bucket.

Murphy's Oil Soap is OK on intact finishes, but if there are any defects in the finish it can get under the finish and cause lifting of the finish.

Paint thinner and a lot of paper towels has the least chance of damaging the finish.

Open doors and windows since paint thinner vapor is flammable.

Here's a picture incase that link didn't work.

I did mop it with warm water after I swept it really well. It still had drywall dust on it. The mop got a lot up but not all.

Paint thinner, really? That sounds like it could be damaging to what finish is left on it.

I use Mineral Spirits, which I think is very similar if not the same as paint thinner. You moisten a paper towel or cloth with it and wipe. It doesn't come in contact with the floor finish long enough to hurt it.

"I did mop it with warm water after I swept it really well. It still had drywall dust on it. The mop got a lot up but not all."

It is now going to be even harder to get the rest up.

It is now drywall mud sticking in every scratch and crevice.

"Paint thinner, really? That sounds like it could be damaging to what finish is left on it. "

Paint thinner will not harm ANY finish except maybe latex paint.
It is even safe on shellac (and shellac can easily be destroyed by water left on the surface).

Varnish, polyurethane (water or oil based), lacquer, shellac, all are safe to clean with paint thinner.

Thanks for all the replies. Good suggestions.

My flooring guy who recently coated a bunch of my old floors said for the rooms without new finish we should use liquid gold. The instructions were to mop clean with murphys then put liquid gold on it heavily and let it soak in for a few days with good ventilation. Worked amazing for the rooms upstairs which were a bit faded and dirty, just be wary for the first few days after as it will be slick.

They shine like brand new today and they are almost 90 years old. Hopefully this helps.