If buffing is not enough, you will have to sand the floor instead. This process usually takes 3 successions, from a heavy grit (30-40) to medium (50-60) to fine grit (80-100).
Some professional hardwood floor refinishing companies offer dustless sanding, where they connect the sanding machines to vacuums to minimize dust.
There are two kinds of sanders that are commonly used: orbital sanders and drum sanders. Orbital ones are easier to handle if you DIY and are recommended for flat surfaces. Drum sanders are used for wavy surfaces and are better handled by a professional.
Once you’re ready with your sander using a heavy grit sandpaper, start at the farthest end of the room and move the sander in the same direction as the grain. When one row is finished, return back along the next row, with an overlap of about an inch with the previous row.
Because the room edges and corners are harder to reach using a large sander, use a hand sander instead. After sanding, make sure to vacuum the surface thoroughly in preparation for the succeeding sanding process. You should also apply wood filler to cracks and holes after sanding.
For the second and third sanding pass, use the same process as above. For the second pass, use a medium grit sandpaper, and for the third pass, use a fine grit sandpaper.
After the final pass, clean up the surface as well as walls and other items with a vacuum cleaner. After that, apply mineral spirits on the floor with a rag