How to remove mortar from salvaged vintage marble window sills
Hello, All! DH and I are renovating a turn-of-the-century gabled ell in a historical neighborhood. I stopped in a nearby salvage place last week and they had marble window sills removed from a nearby school. Looks like Carrara marble to me--white with fine gray veining.
On the underside of each sill are 2 or 3 blobs of mortar which held the window sills in place. Some of the mortar blobs also have a single nail sticking out. How can I remove the mortar? Should I use acid? Should I try to chisel it off?
More info: I got these sills for $15 each, they're about 4' by 6', 3/4' thick. They will look perfect if I can use them as open shelves in my kitchen (I plan to use aged brass brackets to support them). The tops of the sills are polished (glossy), the bottoms are smooth but not shiny (honed?). Because it is an old house and we're selectively remodeling, I don't mind if they don't looke brand new when I'm finished with them. If I have to use some sort of acid on them, I don't mind if they eat away at the marble a bit. I just want a simple solution, but one that won't destroy them. In fact, if my 'solution' left them with a honed instead of polished look, I'd love it. I prefer honed to polished, especially for this house.
I took a picture of the sills to post, but I'm not sure how....
Here is a link that might be useful: Our Crumble Abode