When cleaning paint on your stucco exterior, you will need to be careful how you go about it. The easiest way to clean the stucco without damaging the paint is to use a pressure washer on a low setting. A high setting may blast the paint off of the stucco. If it is really dirty, or has mold forming, use a cleaner made especially for the task. Avoid using a harsh household cleaner that you may just have on hand. If you notice any chalky areas after cleaning, you need to add a stucco conditioner to bond the stucco to avoid damage.