How does one remove spray paint from brick and cement

I guess you should see an attorney or chalk this one up to experience. Getting paint off brick or mortar (It's not cement, I hope) is not easy.

How old is the wall? Old means the brick is dirty and while that might have reduced the ability of the paint to stick, it also means the entire wall will need to be evenly cleaned or it will show. Even if the brick is new, you may find that the only way of removing the paint (usually involves sand blasting) will change the texture of the brick so it will look bad. Also sand blasting and some cleaners can damage the surface of the brick allowing it to absorb additional water causing problems if you live in an area subject to freezing.

I suggest that you think this one out carefully before preceding. Without knowing more about the type of paint, the type and condition of the brick the amount of coverage etc, it would be very difficult to recommend any one procedure.

Call your city's Public Works department and ask what they use to remove graffitti.

CWM

yeah schools have spray cans of super duper paint remover designed for this. pricey but it works

If you're dealing with a relatively small area, try this stuff. It is absolutly amazing. Do a small test spot first.