Acrylic fabrics are appropriate for either indoor or outdoor use. Solutions dyed acrylic features a soil and stain-resistant finish that can be cleaned with a solution of natural soap in lukewarm water. Solution-dyed acrylic does not promote mildew growth. However, mildew may grow on dirt and other foreign substances that are allowed to stand on the fabric. For mildew stains, prepare a mild solution of one cup bleach plus two capfuls of a natural soap per gallon of water. Sponge thoroughly with clean water and air dry.