How to remove blotches of cement from the floors and walls of newly constructed houses?

Answer 1

you could use a metal putty knife on the floor and a plastic on on the walls. a chisel? you may have to do spot repairs on the wall. it really depends. are the floors and walls bare? this question has so many variants.

Answer 2

Are you talking about the basement walls getting splattered when they pour the floor? If so, the easiest way is an air chisel with the widest spade you can fit on it (takes less time that way).