I am sure there are a few folks out there who have used future floor polish to make washes and stains for miniatures in the past.
As for the recipe in question, here it is:
1. One bottle of Clear Floor Finish.
2. Black India Ink
3. Brown India Ink
4. A Tap
5. A container with a VERY tight lid (I would recommend a large mason jar)
1. In the Mason Jar put in 150 mL of Future Floor Finish.
2. Add 30 mL of black ink, and 30 mL of brown ink. Then, add 60 mL of water.
3. Mix well and let it sit (Until all the bubbles are gone).
After that, you use it as you would any other wash or dip - flow it onto a basecoated miniature for instant shading. It won't win you any painting awards, but it will help you get good tabletop standard miniatures out quickly. Just make sure not to forget the matte finish!
For my recipe, I could not source brown India ink locally, so I used an acrylic ink instead. So far my house has not burned down, and all seems to be fine. Except that the brown pigment seems to settle out a bit on the bottom.
For my first victim, I started painting my Tabletop World Windmill. I cheated a bit, in that I primed the main building grey, and the roof brown. From there, it was a heavy drybrush of light grey for the building, with brown, blue, and silver for the wood, windows, and metal, respectively. For the roof, I drybrushed two shades of blue on the shingles, and two shades of brown on the wood. The metal was done in silver. Then I applied the wash, and that is as far as I have gotten (no matte finish yet). I might do one more round of drybrushing, and a bit of inking on the bricks, but the building is mostly done, save for the sails.
It certainly helps that the Tabletop World scenery is top notch. This stuff practically paints itself.