Just last week, vandals spray painted graffiti onto the whitewashed plaster walls of San Xavier Mission outside Tucson, Arizona. The mission was founded by Jesuits in 1692, and the current church began by the Franciscans in 1783. It's one of the oldest buildings in Arizona, a national monument and, in spite of a remarkable level of preservation, in the midst of a multi-million dollar restoration. (I know a bit about the costs of restoration; my firm offices in a 1914 Prairie style building in downtown Phoenix. Check out our restoration.)
Cleaning crews spent last Thursday removing "Rape" and "666" from the exterior walls, and re-plastering. Thank goodness the vandals did not get inside the mission; I've seen the incredible frescoes and statuary, hundreds of years old, creative by Native Americans converts.
We get into the occasional graffiti removal job in conjunction with offering full service commercial office cleaning and janitorial service in the greater Phoenix area. We don't get quite as far afield as Tucson (120 miles down the road), but we do service a number of communities between here and there - Chandler, Gilbert, Maricopa, and even a bit in the San Tan Valley, so a maintenance issue it the Tucson area feels like our own neighborhood. Speaking of neighborhoods, I chair the preservation association in the historic neighborhood where I live; we've had good luck combating graffiti taggers, on rock or brick surfaces that are hard to clean, by applying a clear sacrificial coating (before the graffiti hits). The spray paint scrubs off with the coating, quite easily; we then just reapply the coating. Been trying to convince a few of my clients of the wisdom of prevention rather than restoration.