We bought standard black and red spray paint from the local hardware store and “tagged” four different areas of a building wall. On the left-hand side, we used the Odorless Mineral Spirits and on the right, MEK. While the Mineral Spirits decreased the visibility of the paint, the MEK eliminated the paint much more effectively.
In addition, the solvent had no effect on the gel coat, so the originally-intended color of the building remains intact. So if you find that you need a graffiti-free equipment building that can withstand the abuse of clandestine artists, specify a Shelter Works prefabricated fiberglass building.