for regular use to get up motor oil and such I usually buy the 40lb bag of "oil dry". Sprinkle it on the oil and let it soak it up. Then I will pour out some and rub it in real good with my foot and the floor will come clean. Once I did that the spots were usually cleaner than the rest of the floor
So, depends on the job. Soak up oil, get up spots or as Charlie says muriatic acid if cleaning to paint. Take you choice:)
Now I have a painted floor and just wipe it up!
