How do you remove smoke stain from a marble fire place?

I have cleaned old white marble using a paste of baking soda and hydrogen peroxide and that worked as long as the stain isn't too deep. (Be careful about where the solution drips because it will bleach it out.) Make the paste and let it stay on the surface for a long while. I left mine on for about an hour, checking it periodically.

Try magic eraser..

Hi Nora, perhaps this article will help - https://www.hunker.com/13421548/how-to-clean-soot-from-marble

Full strength ammonia will start to dissolve the coating but will smear. The trick is to dip ammonia cloth into some wood ash (fine); and together they will scour the surface. Wipe before it dries.

I just received my bottles of GS66 from QVC, i put a little bit on a cloth (full Strength) and did a spot on my fireplace. it took a little scrubbing but it looks great. I will use it in a spray bottle and try a little bigger brick. I am sure it will work on Marble. it is a great cleaning product. it will clean anything, and it is concentrated. so you get 2 bottles, and they are 22 oz. and it takes 1 oz for a gallon water. lasts forever.

good luck,