Abstract: A method of cleaning a photoactive and/or hydrophilic surface includes contacting the surface with conditioned water and optionally a cleaning agent solution. A device for cleaning a photoactive and/or hydrophilic surface includes a housing having an inlet and an outlet, a first chamber and an optional second chamber located in the housing, a flow passage extending through the housing between the inlet and the outlet, and a selector valve configured to selectively place the flow passage in flow communication with the first chamber, the optional second chamber, neither chamber, or both chambers. In one embodiment, the first chamber includes an ion exchange bed and the second chamber includes at least one cleaning agent.