Re: cemented interior walls
Sounds like you have plaster walls. Originally, 1/4"x1-1/2" lath was nailed to the walls with gaps between them for the plaster to "key" into. With the advent of drywall, it was faster and easier to hang sheets of drywall with holes in it as the base for the plaster. The holes in the drywall acted as the "key" points to hold the plaster.
The only way to remove the plaster is to remove the drywall with it, all the way to bare studs. Even if you could only get the plaster off, there would be so much damage left behind that the drywall would not be salvageable.
The easiest way to remove it is with a sawzall with a general purpose blade. You cut between the studs vertically, then make a cut or two horizontally. Rack the pieces back and forth will loosen it from it's fasteners, if necessary a prybar behind it on the stud will remove it from the wall. Be very cautious of plumbing and electrical within the wall while cutting.
This is going to be a dusty/messy endeavor, so wear a dust mask, goggles, gloves while working, and you'll also want to use tarps and d****s to seal the area off from the rest of the house and to protect floors and furniture.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!