Cleaning tile grout

[John Morgan]

I'm buying a SFH to rent out that has two tiled bathtub showers that have nasty black mold in the tile grout. I'm weighing the decision to demo the these bathtub showers with new tiled showers or to find a company that can clean the grout. It would obviously be cheaper to find someone to come out and bring the grout color back to life. Has anyone had any luck just cleaning and scrubbing it? It's really nasty looking!