If you want to maintain the original finish of the fireplace, it is recommended to protect it from severe dust, rain, and snow.

At least once a year remove the media and examine the burner. Keep the burner clean by vacuuming or brushing it annually. Make sure the burner porting and burner air openings are free of obstructions at all times. Inspect the area around the burner. Remove any lint or foreign material with a brush or a vacuum cleaner.

The concrete can be cleaned with a mild soap and water solution. Never use abrasives or strong chemicals as they may scratch and/or stain the surface. 

To renew the finish on a firetable it is recommended to re- sea/ re-colour the firetables. Ask the seller with what exactly the surface was finished.