Remove the old fireplace screen and take it outdoors.
Wash the fireplace screen with a water-based degreaser and a coarse brush. Rinse the screen. Allow the screen to dry in the sun for 1 to 2 hours.
Place the fireplace screen on a heavy-duty fabric drop cloth.
Coat one side of the old fireplace screen with galvanized metal self-etching spray primer. Maintain a distance of 8 inches between the fireplace screen and the spray nozzle as you apply. Wait 2 hours for the self-etching primer to dry. Flip the screen over and prime the other side. Wait 4 hours for the self-etching primer to cure.
Coat one side of the primed fireplace screen with a high-temperature spray enamel. Maintain a distance of 8 inches between the fireplace screen and the spray nozzle as you apply. Wait 2 hours for the high-temperature enamel to dry. Flip the screen over and apply enamel to the other side. Wait 6 hours before reattaching the screen.