While this method will work fine for statues tile and marble countertops sanding large areas of marble like marble floors requires a completely different process and technique.
Marble substrate sanding.
Dirt and dust will compress into the marble further scarring or discoloring the surface.
Use special silicone carbide sandpaper in range of grits to slowly work out those imperfections.
This will require using a wet sanding process to achieve the desired results.
Sanding marble is a time consuming process.
Make sure the dish soap you use does not contain any.
Although it is a naturally occurring stone marble is a soft substance with a surface that is easily worn down with regular usage.
Add two drops of gentle dish soap into the warm water.
Step 1 fill a large container or bowl with warm water.
An experiment on polishing marble bianco carrara using orbital sander and diamond polishing sheet since orbital sander do not have water feeding structure.
Dirt and scratches can affect marble.
Marble floor polishing can remove small scratches.