This question has options. How would someone go about accomplishing this goal?
how to remove stains from marble

Choices:
[I] Mix a few drops of ammonia with 12% hydrogen peroxide to spot clean the stained area. However, be careful when using this method on darker stones as the hydrogen peroxide can lighten the color of the marble.
[II] Mix a few drops of ammonia with 12% hydrogen peroxide to spot clean the stained area. However, be careful when using this method on darker stones as the hydrogen peroxide can darken the color of the marble.
[I]