3 Steps for Cleaning Cast Stone

Best Practices for Cleaning Cast Stone

One of the best materials for the garden, cast stone looks like natural stone but can be any shape imaginable. Cast stone offers many forms and uses, from fountains, planters, birdbaths, and sculptures. Its use goes back centuries, used in the buildings and structures of the past. It is a durable and reliable material that will offer a lifetime of enjoyment for all garden decor. Like any stone, cast stone is porous; it will absorb moisture and liquids. 

Ensure that all cast stone pieces are cleaned during the warmer months of the year. The addition of water to cast stone during freezing temperatures can lead to freeze-thaw damage. In colder climates, special attention should be given to fountains. It is crucial to cover, drain, and dry a fountain before the first frost. Here are the best practices for cleaning and maintaining cast stone to preserve your Campania International piece.


  • Bucket for mixing solutions
  • Small soft bristle brush for getting the details.
  • Medium-sized bristle brush for larger areas
  • Soft sponge
  • Hose end sprayer with several settings
  • Garden Hose

Step 1:  Start cleaning your cast stone statue, fountain, birdbath, or planter is to clean it while it is dry. Using a soft to medium bristle brush, gently remove any moss or large algae buildup—dust off the dirt and any large stuck-on debris. 

Step 2: Start by spraying the piece first using just water. Get the whole item wet, but do not soak it for an extended time. Using a soft sponge, wipe down the area and clean the crevasses with a soft bristle brush. Rinse well and repeat with your cleaning solution, rinsing well after each pass. Rinse well. Leaving cleaner or not getting all the debris can cause streaking of the finish.

Water is the best cleaning solution. Use only mild cleaners if you have an excess of algae or dirt. It is always a good idea to test a small area with your solution to be sure it does not damage the patina.

  • Spot cleaning with a 50/50 mix of vinegar and water will help remove calcification that comes from our water, and it helps remove some algae. This technique is excellent for fountains and birdbaths.
  • Clean with a neutral pH soap and water to remove excess algae and dirt. Original Dawn dishwashing liquid is a good choice.

To Maintain the Finish of the Cast Stone:

  • Do not use bleach or harsh cleaning agents. 
  • Do not use a pressure washer. 
  • Do not use acid-base cleaners.
  • Do not use metal brushes or scrapers.

Step 3: The final step in the cleaning process is to allow your cast stone to air dry. Place the item in a dry, protected area for smaller items like statues, birdbaths, and planters. For heavier items, like fountains, large sculptures, benches, or urns, raise them off the ground with bricks or similar. The air needs to pass around the item for it to be completely dry. Before placing your item back in the garden, this step ensures that the whole piece is maintained well.