A method to minimize applying joint compound and sanding by illuminating an area of the gypsum board to show anomalies thereon includes a step of providing a plurality of wireless lighting devices operable by a common remote controller, a step of removably attaching these devices in a spaced-apart arrangement and using the remote controller to energize all lighting devices to identify remaining anomalies. All lighting devices are turned off once the next coat of joint compound is applied and then turned on after it dries to illuminate the remaining surface anomalies. Operation of lighting devices is accomplished without removing or repositioning thereof to assure consistency of illumination over the entire work period.