There are several ways to remove graffiti however the most effective way is by sandblasting. Sandblasting not only removes graffiti but prepares the surface for coatings (anti graffiti coatings) that will allow you to pressure wash off any future problems. These coatings will prevent graffiti from binding to the surface. When a surface is properly prepared the money that you will save over time can be staggering.
It is common practice for individuals with this problem to paint over the graffiti. In some cases this may be possible. In other cases the underlying paint will bleed through the new paint. In other graffiti removal procedures there is still a reminence of what is being removed. Chemicals and Solvents are readily available at most local hardware stores. These are designed to remove the graffiti but can be toxic and dangerous for the environment.
Some surfaces are more difficult then others. Surfaces such as concrete or brick work for example have porous surfaces which make removing the paint almost impossible through chemicals a loan. Sandblasting these surfaces is not only cost efficient but sandblasters can reach a large area in a very short amount of time. Some graffiti can not only be offensive but may be dangerous depending on the author/artist.. Quick removal can be invaluable.