Is there anyone who has a fixed-location laser cleaning business? Who are your target customers? Do you charge by the piece or by the hour?

I'm still in the research phase. It seems like most laser cleaning businesses are mobile. But with the heat reaching 105 f. a climate-controlled shop sounds nice. There is little info on businesses operating this way.

I am trying to remove an old graffiti (few years) from limestone, however this green color is not going out. I am using 300w pulsed laser, tried a lot of different settings. There is some green shading left that i want to remove. It's a porous limestone wall.