An Experiment in Removing Spray Paint Graffiti from Hohokam Rock Art with Graffiti-B-Gone

In December 1994, an Arizona Site Steward notified the Phoenix City Archaeologist that a major rock art panel in South Mountain Park had been spray painted with graffiti. At least 700 years old, this Hohokam petroglyph panel is located on a dense, patinated, granodiorite boulder near a city street at the northern edge of the park's boundary. Spray paint graffiti had previously been placed on city structures along the street, as well as on several petroglyph boulders within the park, but this act of vandalism was the first time for this particular panel. Because the panel was located near a residential area, and the graffiti was large and very obvious, the park rangers believed there was a high probability that more graffiti would soon follow, either on that panel or on other nearby boulders. The ranger's standard procedure in such cases was to cover the graffiti with paint that attempted to match the color of the stone. That strategy, however, was considered inappropriate by the City Archaeologist since additional paint would further cover and negatively impact the rock art underneath and next to the graffiti. Consequently, the rangers challenged the archaeologist to find a solution to the problem, a problem for which archaeologists receive little or no training in graduate school or elsewhere. This paper discusses how the problem was approached with the assistance of a conservator, centered around an experiment in removing the graffiti with a graffiti removal product called Graffiti-B-Gone.