plaster over foundation coating

I'm exposing some of my foundation wall and want to plaster or stucco over it to make it more decorative. The foundation is poured concrete, but since it was previously buried, it was also coated with foundation coating. So my question is how to remove the black foundation coating so that a plaster will adhere to the concrete. As an alternative, I might decide to apply a faux stone instead of the plaster.

I've tried solvent, sandblasting, and even one of those attachments for a drill that looks much like a very coarse scotchbrite pad. Nothing works well enough. I have maybe 40 sqft to clean up. Any thoughts?

njescapee

 

If sand blasting didn't work, I don't know what will. Even if you remove that stuff, I don't think the plaster will last.

 

Paint might be an option.

 

I would never paint cement or bricks.