Welcome to the second post about brick walls construction (THIS is the first one).
As for the basement floor, after placing the bricks I proceed finishing the walls with sandpaper and filling the joints with cement.
To polish the surface I use a little tool made by myself pasting sandpaper to a wooden support. This will allow me to reach corners and edges better than with my hands.
After some bad experience I've learned to close my eyes in time and to move away my face from the miniature before to breathe again...