Soap scum or limescale is a filmy layer of material which forms around showers, sinks, tubs, and other areas where soap and water are often present together. It is caused by the minerals which are naturally present in water. When these minerals combine with soap, they create a sticky mixture which adheres to surrounding surfaces, slowly creating a scaly buildup which may also include body oils, dead skin, hair, and dirt. For many people, soap scum is a regular cleaning bugbear, especially if they live in areas with hard water.

Regular soap scum is white to gray in color. However, the soap scum often acts as an ideal substrate for algae and molds, and it may develop a rainbow of colors along with some undesirable odors. When soap scum is allowed to build up to this point, it can also become very difficult to remove. Only heavy scrubbing and a strong cleaner will be able to penetrate the layers of soap scum.

Most people are less interested in knowing what soap scum is and more interested in knowing how to get rid of it. The best way to deal with soap scum is to clean regularly, preventing the buildup from becoming firmly adhered. Wiping down tubs, showers, sinks, and tile at least once a week can often keep soap scum to a minimum, especially if ammonia or vinegar is added to the sponge or cloth used for wiping, as these substances will cut through the soap scum. Detergent can also remove soap scum. Wiping down a tub after using bath oils is also highly recommended.

Some people use wax and other products designed to increase water resistance to reduce soap scum by preventing the deposition of water on the walls of showers and tubs. This can be effective in some cases, but the wax can also become very messy, and it needs to be routinely stripped and reapplied.

For more heavy-duty cleaning, a commercial degreaser is often very effective against soap scum. You can also use cleaning products formulated for soap scum, or you can utilize lemon juice, vinegar, or ammonia. A paste of baking soda and water can also work, with the baking soda acting as an abrasive to lift away the layers of soap scum. When you use heavy cleaners, please remember to leave a window open and wear gloves so that the cleaners do not irritate your lungs or hands.