Mildew stains often make an appearance in damp locations, such as bathrooms and basements. Before painting, you'll need to eliminate this black, speckled growth to make sure new coats of paint adhere well.
Tools and Materials
| Sponge | Bucket | Sandpaper |
| Rubber gloves | Eye protection | Drop cloth |
| TSP solution | Bleach solution | |
Step 1. Test the stains by washing with some warm water and mild detergent. Ordinary stains will wash out, but mildew won't. If the stains don't wash out, gently sand them out with 150-grit sandpaper. 
Step 2. Put on some rubber gloves and eye protection before you wash walls with bleach, which will kill the mildew spores. After the bleach treatment, wash mildew away with some TSP solution or a phosphate-free substitute, then rinse the area with clear water. Allow the wall to completely dry. 