Luckily, while it is annoying to see graffiti on your private property, it can be eliminated pretty easily.
Paint over it — Just about the easiest way to get rid of graffiti is to paint over it. If it has been sprayed on a door, a gate or a wall, why not take this opportunity to give it a new coat of paint, and paint over the offending piece. Not only will it disappear quickly under a coat of paint, but the outside of your house or business will look spiffy and new.
Call the council — If it is on public property, calling the city council can often get rid of it. Many city councils have graffiti crews whose job it is to get rid of new or old graffiti. Just give your council a call and see if it is possible to remove it. If it is lewd or with rude writing, chances are they will remove it quickly.
Use a paint thinner — Another great way to remove graffiti is to use a paint thinner. You can buy them at any do it yourself store or hardware shop, and they go to work fast removing the graffiti paint. Just spray it on or brush it on, leave it for a moment and then wipe the wall, door or fence clean. In most cases, it only takes one or two attempts before the paint will completely disappear.