Alkaline in-use solutions that may be used to disinfect and/or sanitize hard surfaces and which may act as anti-biofilm agents, comprise a disinfectant/sanitizer cleaner solution and an activator solution that are mixed together to form the alkaline in-use solutions. Disinfectant/sanitizer cleaner solution may comprise quaternary ammonium compound and hydrogen peroxide. Activator solution may comprise alkaline buffering agent, chelating agent and soluble silicon dioxide. These solutions are safe for use on aluminum and other soft (easily-corroded) metal surfaces, and safe for use on plastic surfaces.
