We installed carrara marble floors in our new master bathroom. Tile company came back for some routine punch-out work - stuff like grout/caulk touch ups from the house settling, etc. One of the items they had to fix was removing some left over pencil marks on the tile from the original measuring/cutting process - we were unable to get it out with soap/water or an eraser, so we figured the tile installers would have some trick.

Turns out their trick was to use a solution designed for a solution designed as a pre-grind cleaner/etcher for CONCRETE surfaces. The specified application is to prep a concrete surface to accept stain. I actually caught them using it - when they poured the solution on to the marble, it actually reacted and started foaming up like you'd see when you mix baking soda with vinegar for that gradeschool science experiment.

We now have big, thick lines and blobs where the marble is very dull - quite noticeable just walking on it if you look down at all. I guess it sort of qualifies as etching, but from a very different source than normal cleaning products, spilled juice, etc.

What's our remedy here? Is there a way to even things out so these giant lines/splotches are less apparent? I don't particularly mind some variation in our floors - we knew marble would kind of wear in over time - but we were hoping to kind of organically get some wear patterns in, not have striking differences and harsh lines all across the floor. I'm also not sure if this solution would have eaten away at some spots which would make them more susceptible to holding dirt/stains/mildew/whatever vs. the smoother/shinier surfaces.

Our GC is being as helpful as he can, but this is now the second or third time the tile installer has messed up warranty service. If we even allow them to come back, I want to have an understanding of what's actually a good idea vs. what they might be trying to do just to cover things up enough for them to exit the project. Help!