Heavy carbon buildup removal / restore limestone

[Racer]

We’ve had a couple of long threads about this in past year. Look under historic restoration.

Here is one of them.

What chemical would you choose?

Thank you all for your input, I love it. So, here’s our (we’re in this together, right?) plan, folks: I’m shooting these pictures over to ecochem, prosoco, and my local stone provider. I’ll ask the stone provider if they have any experience with any of the other possible solutions; limonene, sh, peroxide, etc. I have a feeling the stone provider is already going to have prior knowledge of prosoco and, if not, those two are getting an introduction. I’m much more interested in buying products f…