Regular cleaning of dust can be completed with a clean damp sponge and a mild detergent. All of our Concrete Creations, including our fire bowls will age, and might get water marks. Most people view the water marks as part of the natural look of aging concrete; however, if it bothers you there is a way to clean the water marks. 1) Prepare and Mix: 5 parts water to 1 part white distilled vinegar. (Adjust the strength as needed. You can also use commercial grade hydrochloric acid for cleaning). 2) Wet the outside surface of the bowl thoroughly with clean water. 3) Use a plastic brush with soft bristles to brush affected areas with the cleaning solution, to remove whitening or staining. 4) Hose the affected areas off with clean water immediately once the whitening or staining has cleared, or when a change in appearance is observed. 5) Repeat the process at least two times to ensure efficiency of the acid solution. If only slightly improving, reduce the ratio of water to acid and repeat the same process. 6) Once the surface is clean, let dry for 24-hours, and then reseal immediately for protection.