Merchants and businesses support painting and cleaning along commercial street blocks. Neighbourhood volunteer programs clean up graffiti on a regular basis. Don't ignore graffiti. Clean it up as soon as you notice it. This helps to stop it from spreading.
Fast action improves the chances of a good clean-up.
Your best option in many cases, may be to simply paint over the graffiti. If you see vandals in the act, write down a description of their appearance and report it immediately to the Police Department at 911. Alert neighbours if you spot graffiti on their property and encourage them to clean it up. If there is graffiti on more than one property, it may be possible to share the cost and the labour to clean up. Vandalism cannot be prevented, but the damage can be minimized.