An aerosol spray can (12) that can only be operated when connected to an a-c utility power source provided by a power cord (22) that includes a power-line activator (30). Thus, the use of an aerosol spray can (12) to spray graffiti is prevented or at least minimized. The can (12) is modified by attaching to its upper section (14) a valve attachment port (16) to which is attached a lower fluid port (86) located on a slide and twist valve (80). The valve (80) also includes an upper fluid port (84) having a check valve (88) that opens when a standard spray head (26) is depressed and a permanent magnet piston (90) having a fluid passage bore (96). When no power is applied, a compression spring (94) positions the piston (90) with the bore (96) misaligned in both a radial and longitudinal position that prevents the passage of the fluid. Conversely, when power is applied, an electromagnet (36) in the power-line activator (30) aligns the fluid passage bore (96) with the upper and lower fluid ports (84,86) to allow fluid to pass when the spray head (26) is depressed.